Exposure apparatus, exposure method, and device producing method

ABSTRACT

An exposure apparatus is provided with a measuring unit which measures at least one of property and components of a liquid in a state that a liquid immersion area is formed on an object different from a substrate P to be exposed. There is provided an exposure apparatus which can accurately perform exposure process and measurement process through the liquid by judging the state of the liquid in advance and by performing a procedure as appropriate.

TECHNICAL FIELD

The present invention relates to an exposure apparatus and an exposuremethod for exposing a substrate, and a device producing method.

BACKGROUND ART

In photolithography process, as one of the producing processes for amicro device such as a semiconductor device or a liquid crystal displaydevice, an exposure apparatus which projects a pattern formed on a maskonto a photosensitive substrate by exposure is employed. This exposureapparatus has a mask stage supporting a mask and a substrate stagesupporting a substrate, and projects a pattern of a mask to a substratevia a projection optical system while successively moving the mask stageand the substrate stage. In micro device producing, for higherintegration of the device, it has been demanded to increase the finenessof the pattern to be formed on the substrate. To meet this demand,higher resolution of the exposure apparatus has been desired. As one ofthe means for realizing this higher resolution, a liquid immersionexposure apparatus is proposed which fills a liquid in an optical-pathspace between a projection optical system and a substrate and performsan exposure process through the liquid, as disclosed in the followingpatent document 1.

Patent document 1: Pamphlet of International Publication Pamphlet No.99/49504

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

In the liquid immersion exposure apparatus, exposure process andmeasurement process through a liquid are performed, and if the liquid ispolluted or degraded, there is a fear that the results of the exposureprocess and measurement process are affected. Therefore, it is importantto grasp the state of the liquid and take a proper measure.

The present invention has been made taking the foregoing circumstancesinto consideration, and an object thereof is to provide an exposureapparatus, an exposure method and a device producing method in which thestate of the liquid (property, components and the like) can beaccurately grasped.

Means for Solving the Problem

In order to solve the problem, the invention adopts the followingconstructions.

According to a first aspect of the invention, there is provided anexposure apparatus which exposes a substrate by irradiating thesubstrate with an exposure light beam via an optical member, theexposure apparatus comprising: an object which is arranged on alight-exit side of the optical member and is different from thesubstrate; a liquid immersion mechanism which fills an optical pathspace between the optical member and the object with a liquid; and ameasuring unit which measures at least one of property and components ofthe liquid in a state that a liquid immersion area is formed on theobject.

According to the first aspect of the invention, since the state of theliquid can be grasped without contact with the substrate to be exposed,a procedure or treatment for setting the liquid to a desired state canbe taken, and exposure process and measurement process through theliquid can be accurately performed.

According to a second aspect of the invention, there is provided anexposure apparatus which exposes a substrate by irradiating thesubstrate with an exposure light beam via an optical member, theexposure apparatus comprising: a liquid immersion mechanism which fillsa predetermined space on a light-exit side of the optical member with aliquid; and a measuring unit which measures at least one of property andcomponents of the liquid; wherein the liquid immersion mechanism has aflow channel in which the liquid flows, and the measuring unit measuresthe liquid at a first position in the flow channel and measures theliquid at a second position in the flow channel.

According to the second aspect of the invention, since the states of theliquid at the first position in the flow channel of the liquid immersionmechanism and the liquid at the second position in the flow channel canbe grasped, a procedure or treatment for setting the liquid to a desiredstate can be taken, and exposure process and measurement process throughthe liquid can be accurately performed.

According to a third aspect of the invention, there is provided anexposure method for exposing a substrate through a liquid, the methodcomprising: a first step of forming a liquid immersion area on an objectdifferent from the substrate; a second step of inspecting a state of theliquid in a state that the liquid immersion area is formed on theobject; a third step of adjusting an exposure conditions based on aresult of inspection; and a fourth step of exposing the substrate underthe adjusted exposure condition by irradiating the substrate with anexposure light beam through a liquid in the liquid immersion area formedon the substrate.

According to the exposure method of the third aspect of the invention, aliquid immersion area is formed in advance by using an object differentfrom the substrate, and optimum exposure conditions including the stateof the liquid can be set by grasping the state of the liquid to be usedfor the liquid immersion exposure. Accordingly, that exposure processand measurement process can be accurately performed.

According to a fourth aspect of the invention, there is provided anexposure method for exposing a substrate by irradiating the substratewith an exposure light beam through a liquid, the method comprising:flowing the liquid to a predetermined liquid immersion area through aflow channel; detecting a state of the liquid at a first position and asecond position of the flow channel; and forming a liquid immersion areaon the substrate to expose the substrate, based on a result ofdetection.

According to the fourth aspect of the invention, since the states of theliquid at the first position in the flow channel toward the liquidimmersion area and the liquid at the second position can be grasped, theprocedure or treatment for setting the liquid to a desired state can betaken, and the exposure process and measurement process through theliquid can be accurately performed.

According to a fifth aspect of the invention, there is provided a deviceproducing method using the exposure apparatus according to theabove-described aspects. According to the fifth aspect of the invention,a device can be produced by using the exposure apparatus with which theexposure process and measurement process through a liquid can beaccurately performed.

According to a sixth aspect of the invention, there is provided a deviceproducing method, comprising: a step of exposing a substrate by theexposure method according to the above-described aspects; a step ofdeveloping the exposed substrate; and a step of processing the developedsubstrate. According to the sixth aspect of the invention, a device canbe produced by using the exposure method with which exposure process andmeasurement process through a liquid can be accurately performed.

EFFECTS OF THE INVENTION

According to the invention, exposure process and measurement processthrough a liquid can be accurately performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic arrangement view showing an exposure apparatusaccording to a first embodiment;

FIG. 2 is a plan view of a stage viewed from above;

FIG. 3 is a drawing showing a state that a liquid immersion area movesbetween a substrate stage and a measuring stage;

FIG. 4 is a schematic arrangement view showing a liquid supply unit;

FIG. 5 is a schematic arrangement view showing a measuring unit;

FIG. 6 is a flowchart explaining an example of an exposure sequence;

FIG. 7 is a drawing showing a state that a liquid on a substrate ismeasured;

FIG. 8 is a drawing showing an example of the substrate;

FIG. 9 is a drawing showing another example of the substrate;

FIG. 10 is a drawing showing an exposure apparatus according to a secondembodiment;

FIG. 11 is a drawing showing an exposure apparatus according to a thirdembodiment;

FIG. 12 is a drawing showing an exposure apparatus according to a fourthembodiment; and

FIG. 13 is a flowchart showing an example of a semiconductor deviceproducing process.

LEGENDS OF REFERENCE NUMERALS

-   -   1: liquid immersion mechanism, 2: base material, 3:        photosensitive material, 10: liquid supply mechanism, 11: liquid        supply unit, 12: supply port, 13: supply tube, 20: liquid        recovery mechanism, 21: liquid recovery unit, 22: recovery port,        23: recovery tube, 60: measuring unit, 61-64: measuring        instrument, 61K-61K: branched tube, 70: nozzle member, 95: upper        surface, 100: predetermined area, 300: reference member, 120:        functional fluid supply unit, 161: water purifying unit, 162:        ultrapure water-producing unit, 173: degassing unit, 173:        filter, 400, 500, 600: sensor, AR: projection area, C1: first        position, C2: second position, CONT: control unit, DP: dummy        substrate, EL: exposure light beam, EX: exposure apparatus, INF:        reporting unit (informing unit), K1: optical path space, LK:        functional fluid, LR: liquid immersion area, LQ: liquid, MRY:        memory, P: substrate, PL: projection optical system, ST1:        substrate stage, ST2: measuring stage

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the invention will be described withreference to the drawings. However, the invention is not limited to theembodiments.

First Embodiment

FIG. 1 is a schematic arrangement view showing an exposure apparatusaccording to a first embodiment. In FIG. 1, the exposure apparatus EXincludes a mask stage MST which is movable while holding a mask M; asubstrate stage ST1 which includes a substrate holder PH for holding asubstrate P and is movable while holding the substrate P on thesubstrate holder PH; a measuring stage ST2 which is provided with anoptical measuring instrument for optically performing measurementconcerning the exposure process and is movable independently from thesubstrate stage ST1; an illumination optical system IL which illuminatesa mask M held on the mask stage MST with an exposure light beam EL; aprojection optical system PL which projects an image of a pattern on themask M illuminated with the exposure light beam EL to the substrate Pheld on the substrate stage ST1, and which exposes the image of thepattern on the substrate; and a control unit CONT which controls theoverall operation of the exposure apparatus EX. To the control unitCONT, a reporting unit INF which reports information concerning theexposure process is connected. The reporting unit INF includes a displaydevice (display), a warning device which issues a warning (alarm) byusing sound or light, and the like. Furthermore, to the control unitCONT, a memory MRY for storing information concerning the exposureprocess is connected.

The exposure apparatus EX of this embodiment is a liquid immersionexposure apparatus to which a liquid immersion method is applied forimproving the resolution and substantially widening the depth of focusby substantially shortening the exposure wavelength, and which includesa liquid immersion mechanism 1 for filling, with a liquid LQ, an opticalpath space K1 for an exposure light beam EL on a side of an image planeof the projection optical system PL. The liquid immersion mechanism 1includes: a nozzle member 70 which is provided in the vicinity of theimage plane of the projection optical system PL and which has a supplyport 12 for supplying a liquid LQ and a recovery port 22 for recoveringthe liquid LQ; a liquid supply mechanism 10 for supplying the liquid LQto the side of the image plane of the projection optical system PLthrough the supply port 12 provided in the nozzle member 70; and aliquid recovery mechanism 20 for recovering the liquid LQ on the side ofthe image plane of the projection optical system PL through the recoveryport 22 provided in the nozzle member 70. The nozzle member 70 is formedinto an annular shape so as to surround a first optical element LS1which is included in among a plurality of optical elements constructingthe projection optical system PL and is disposed most closely to theimage plane of the projection optical system PL.

The exposure apparatus EX adopts a local liquid immersion method inwhich a liquid immersion area LR, of the liquid LQ supplied from theliquid supply mechanism 10, which is larger than the projection area ARand smaller than the substrate P, is locally formed on a part of thesubstrate P including the projection area AR of the projection opticalsystem PL at least during projection of an image of a pattern on themask M onto the substrate P. Specifically, the exposure apparatus EXfills, with the liquid LQ, an optical path space K1 between a lowersurface LSA of the first optical element LS1 disposed most closely tothe image plane of the projection optical system PL and an upper surfaceof the substrate P arranged on the side of the image plane of theprojection optical system PL, and projects onto the substrate P an imageof a pattern on the mask by irradiating the substrate P with theexposure light beam EL that has passed through the mask M via the liquidLQ between the projection optical system PL (first optical element LS1)and the substrate P and the projection optical system PL (first opticalelement LS1). The control unit CONT locally forms a liquid immersionarea LR of the liquid LQ on the substrate P by supplying a predeterminedamount of the liquid LQ to a surface of the substrate P with the liquidsupply mechanism 10 and by recovering a predetermined amount of theliquid LQ on the substrate P with the liquid recovery mechanism 20.

Further, the exposure apparatus EX has a measuring unit 60 whichmeasures at least one (liquid state) of the property and the componentsof the liquid LQ forming the liquid immersion area LR. The measuringunit 60 measures at least one of the property and components of theliquid LQ filled between the projection optical system PL and the objectarranged on the side of the image plane of the projection optical systemPL. In this embodiment, the measuring unit 60 measures the liquid LQrecovered by the liquid recovery mechanism 20.

In the liquid immersion mechanism 1, the liquid supply mechanism 10includes a functional fluid supply unit 120 capable of supplying afunctional fluid having a predetermined function different from that ofthe liquid LQ for forming the liquid immersion area LR.

This embodiment will now be explained as exemplified by a case using thescanning type exposure apparatus (so-called scanning stepper) as theexposure apparatus EX which exposes a pattern formed on the mask M onthe substrate P while synchronously moving the mask M and the substrateP in mutually different directions (opposite directions) in the scanningdirection. In the following explanation, the X axis direction is thesynchronous movement direction (scanning direction) of the mask M andthe substrate P in a horizontal plane, the Y axis direction(non-scanning direction) is the direction orthogonal to the X axisdirection in the horizontal plane, and the Z axis direction is thedirection which is perpendicular to the X axis direction and the Y axisdirection and is coincident with an optical axis AX of the projectionoptical system PL. The directions of rotation (inclination) about the Xaxis, the Y axis, and the Z axis are θX, θY, and θZ directions,respectively. The term “substrate” used herein includes a substrate witha photosensitive material (resist) coated on a base material of asemiconductor wafer, or the like, and the term “mask” includes a reticleformed with a device pattern to be subjected to the reduction projectionto the substrate.

The illumination optical system IL includes an exposure light source, anoptical integrator which uniformizes the illuminance of a light fluxradiated from the exposure light source, a condenser lens which collectsthe exposure light beam EL from the optical integrator, a relay lenssystem, and a field diaphragm which sets an illumination area on themask M to be illuminated with the exposure light beam EL. Apredetermined illumination area on the mask M is illuminated with theexposure light beam EL having a uniform illuminance distribution by theillumination optical system IL. Lights usable as the exposure light beamEL radiated from the illumination optical system IL include, forexample, emission lines (g-ray, h-ray, i-ray) radiated, for example,from a mercury lamp, far ultraviolet light beams (DUV light beams) suchas the KrF excimer laser beam (wavelength: 248 nm), and vacuumultraviolet light beams (VUV light beams) such as the ArF excimer laserbeam (wavelength: 193 nm) and the F₂ laser beam (wavelength: 157 nm). Inthis embodiment, the ArF excimer laser beam is used.

In this embodiment, as the liquid LQ for forming the liquid immersionarea LR, pure or purified water is used. Pure water can transmitemission lines (g-ray, h-ray, i-ray) radiated, for example, from amercury lamp and far ultraviolet light beams (DUV light beams) such asthe KrF excimer laser beam (wavelength: 248 nm) as well as an ArFexcimer laser beam.

The mask stage MST is movable while holding the mask M. The mask stageMST holds the mask M by vacuum adsorption (or electrostatic adsorption).The mask stage MST is two-dimensionally movable in a plane perpendicularto the optical axis AX of the projection optical system PL, that is, inan XY plane and finely rotatable in the θZ direction while holding themask M by driving of the mask stage driving unit MSTD, including alinear motor and the like, controlled by the control unit CONT. The maskstage MST is also movable in the Z axis direction and finely movable inthe θX and θY directions. On the mask stage MST, a movement mirror 91which moves together with the mask stage MST is fixedly provided. At aposition facing the movement mirror 91, a laser interferometer 92 isprovided. The two-dimensional position and the angle of rotation in theθZ direction (including the angles of rotation in θX and θY directionsaccording to circumstances) of the mask M on the mask stage MST aremeasured by the laser interferometer 92 in real time. The result ofmeasurement by the laser interferometer 92 is outputted to the controlunit CONT. The control unit CONT drives the mask stage driving unit MSTDbased on the result of measurement made by the laser interferometer 92and controls the position of the mask M held on the mask stage MST.

The projection optical system PL projects the image of the pattern onthe mask to the substrate P at a predetermined projection magnificationβ. The projection optical system PL includes a plurality of opticalelements, and these optical elements are held by a barrel PK. In thisembodiment, the projection optical system PL is the reduction systemhaving the projection magnification β which is, for example, ¼, ⅕, or ⅛.The projection optical system PL may be any one of either the samemagnification system or the enlarging system. The projection opticalsystem PL may be any one of a dioptric system including no cataptricelement, a cataptric system including no dioptric element, and acatadioptric system including cataptric and dioptric elements. Among aplurality of optical elements constructing the projection optical systemPL, the first optical element LS1 disposed most closely to the imageplane of the projection optical system PL is exposed from the barrel PK.

The substrate stage ST1 has a substrate holder PH which holds asubstrate P. The substrate stage ST1 is arranged on the side of theimage plane of the projection optical system PL, and is movable on abase member BP on the side of the image plane of the projection opticalsystem. The substrate holder PH holds the substrate P by, for example,vacuum adsorption. On the substrate stage ST1, a concave 96 is provided,and the substrate holder PH for holding the substrate P is arranged inthe concave 96. The upper surface 95 of the substrate stage ST1, exceptfor the concave 96, is formed into a flat surface (flat portion) havingsubstantially the same height (flush with) as the upper surface of thesubstrate P held on the substrate holder P.

The substrate stage ST1 is two-dimensionally movable in an XY plane andfinely rotatable in the θZ direction on the base member BP, whileholding the substrate P via the substrate holder PH, according todriving of the substrate stage driving unit SD1 which includes a linearmotor and the like and which is controlled by control unit CONT.Furthermore, the substrate stage ST1 is also movable in the Z axisdirection, θX direction, and θY direction. Therefore, the upper surfaceof the substrate P supported by the substrate stage ST1 is movable insix free directions of the X axis, Y axis, Z axis, θX, θY, and θZdirections. On a side surface of the substrate stage ST1, a movementmirror 93 that moves together with the substrate stage ST1 is fixedlyprovided. At a position facing the movement mirror 93, a laserinterferometer 94 is provided. The two-dimensional position and theangle of rotation of the substrate P on the substrate stage ST1 aremeasured in real time by the laser interferometer 94. Further, theexposure apparatus EX includes a focus leveling detection system (notshown) using an oblique incidence system which detects surface positioninformation of the upper surface of the substrate P supported on thesubstrate stage ST1 as disclosed in, for example, Japanese PatentApplication Laid-open No. 8-37149. The focus leveling detection systemdetects surface position information of the upper surface of thesubstrate P (positional information in the Z axis direction andinclination information in the θZ and θY directions of the substrate P).The focus leveling detection system may detect surface positioninformation of the substrate P through the liquid LQ in the liquidimmersion area LR, may detect surface position information of thesubstrate P not through the liquid LQ of the liquid immersion area LR,or may be a combination of a system which detects the surface positioninformation of the substrate P through the liquid LQ and a system whichdetects surface position information of the substrate P not through theliquid LQ. Alternatively, the focus leveling detection system may adopta system using a capacitance type sensor. The result of measurement madeby the laser interferometer 94 is outputted to the control unit CONT.The result of detection by the focus leveling detection system is alsooutputted to the control unit CONT. The control unit CONT matches theupper surface of the substrate P with the image plane of the projectionoptical system by driving the substrate stage driving unit SD1 based onthe result of detection by the focus leveling detection system and bycontrolling the focus position (Z position) and angles of inclination(θX and θY) of the substrate P, and performs positional control in the Xaxis direction, Y axis direction, and θZ direction of the substrate Pbased on the result of measurement made by the laser interferometer 94.

The measuring stage ST2 is provided with various optical measuringinstruments (including measuring members) for optically performingmeasurements concerning the exposure process. The measuring stage ST2 isarranged on the side of the image plane of the projection optical systemPL, and is movable on the base member BP on the side of the image planeof the projection optical system PL. The measuring stage ST2 istwo-dimensionally movable in an XY plane and finely rotatable in the θZdirection on the base member BP by the driving of the measuring stagedriving unit SD2, which includes a linear motor and the like and whichis controlled by the control unit CONT, in a state that the opticalmeasuring instruments are provided on the measuring stage ST2.Furthermore, the measuring stage ST2 is also movable in the Z axisdirection, θX direction, and θY direction. Therefore, the measuringstage ST2 is movable in the six free directions of the X axis, Y axis, Zaxis, θX, θY, and θZ directions similarly to the substrate stage ST1. Ona side surface of the measuring stage ST2, a movement mirror 98 movabletogether with the measuring stage ST2 is fixedly provided. At a positionfacing the movement mirror 98, a laser interferometer 99 is provided.The two-dimensional position and angle of rotation of the measuringstage ST2 are measured in real time by the laser interferometer 99, andthe control unit CONT controls the position of the measuring stage ST2based on the result of measurement by the laser interferometer 99.

The control unit CONT can move the substrate stage ST1 and the measuringstage ST2 independently from each other on the base BP by using thestage driving unit SD1 and the stage driving unit SD2, respectively. Thecontrol unit CONT can make the upper surface 95 of the substrate stageST1 or the upper surface of the substrate P held on the substrate stageST1 face the lower surface LSA of the projection optical system PL bymoving the substrate stage ST1 to a position below or under theprojection optical system PL. Similarly, the control unit CONT can makethe upper surface 97 of the measuring stage ST2 face the lower surfaceLSA of the projection optical system PL by moving the measuring stageST2 to a position below or under the projection optical system PL.

The substrate stage ST1 and the measuring stage ST2 are provided atpositions side by side, and the upper surface 95 of the substrate stageST1 including the upper surface of the substrate P and the upper surface97 of the measuring stage ST2 are provided at a substantially sameposition in height.

FIG. 2 is a plan view of the substrate stage ST1 and the measuring stageST2 as seen from above. In FIG. 20 on the upper surface 97 of themeasuring stage ST2, a reference member 300 is provided as an opticalmeasuring instrument (measuring member). The reference member 300 isused when a positional relationship (baseline amount) between aprojection position of the image of the pattern and a detectionreference of a substrate alignment system (not shown) in the XY plane ismeasured for defining or determining an alignment position of thesubstrate P with respect to the image of the pattern on the mask M viathe projection optical system PL. On the upper surface 301 of thereference member 300, a first reference mark MFM and a second referencemark PFM are formed in a predetermined positional relationship. Thefirst reference mark MFM is detected by a mask alignment system of theVRA (visual reticle alignment) system as disclosed in, for example,Japanese Patent Application Laid-open No. 7-176468. The mask alignmentsystem of the VRA system measures the position of the mark byirradiating the mark with light and processing image data of the markimaged with a CCD camera or the like. The second reference mark PFM isdetected by a substrate alignment system of the FIA (field imagealignment) system as disclosed in Japanese Patent Application Laid-openNo. 4-65603. The substrate alignment system of the FIA system irradiatesa target mark with a detecting light flux which is broadband so that aphotosensitive material on the substrate P is not exposed thereto,picks-up an image of the target mark formed on a light receiving surfacedue to a light reflected from the target mark and an image of an indexthat is not shown (index pattern on an index plate provided in thesubstrate alignment system) by using an image pickup device (CCD or thelike), and process image pickup signals of these images to measure theposition of the mark.

On the upper surface 97 of the measuring stage ST2, an upper plateconstructing a part of an unevenness sensor 400 as an optical measuringinstrument for measuring illuminance unevenness as disclosed in JapanesePatent Application Laid-open No. 57-117238 and/or measuring afluctuation amount of transmittance of the projection optical system PLwith respect to the exposure light beam EL as disclosed in JapanesePatent Application Laid-open No. 2001-267239, an upper plateconstructing a part of an spatial image measuring sensor 500 asdisclosed in Japanese Patent Application Laid-open No. 2002-14005, andan upper plate constructing a part of an irradiance sensor (illuminancesensor) 600 as disclosed in Japanese Patent Application Laid-open No.11-16816, are provided. On the upper surface 97 of the measuring stageST2, the upper surfaces 401, 501, and 601 of these sensors 400, 500, and600, respectively, are arranged.

In this embodiment, the upper surface 97 of the measuring stage ST2including the upper surfaces 301, 401, 501, and 601 of the opticalmeasuring instruments 300, 400, 500 and 600, respectively, issubstantially flat, and the upper surface 97 of the measuring stage ST2and the upper surfaces 301, 401, 501 and 601 of the optical measuringinstruments 300, 400, 500 and 600, respectively, are substantially flushwith one another.

In this embodiment, the first reference mark MFM formed on the referencemember 300 is detected by the mask alignment system via the projectionoptical system PL and the liquid LQ, and the second reference mark PFMis detected by the substrate alignment system not via the projectionoptical system PL and the liquid LQ. In this embodiment, since liquidimmersion exposure process for exposing the substrate P is performed byirradiating the substrate P with an exposure light beam EL via theprojection optical system PL and the liquid LQ, the unevenness sensor400, the spatial image measuring sensor 500, the irradiance sensor 600and the like, which perform the measurement process using the exposurelight beam EL, receive the exposure light beam EL via the projectionoptical system PL and the liquid LQ according to the liquid immersionexposure process.

Thus, the measuring stage ST2 is a dedicated stage for performing ameasurement process concerning the exposure process, and does not holdthe substrate P. The substrate stage ST1 is not provided with anyoptical measuring instrument for performing measurements concerning theexposure process. The measuring stage ST2 is disclosed in detail in, forexample, Japanese Patent Application Laid-open No. 11-135400, EuropeanPatent Publication No. 1,041,357, and the like.

Only parts of, for example, the optical systems of the sensors 400, 500,and 600 may be installed in the measuring stage ST2, or the entiresensors may be installed in the measuring stage ST2. The opticalmeasuring instruments to be installed in the measuring stage ST2 are notlimited to the above-described sensors 400, 500, 600 and the referencemember 300, and any optical instrument(s) (measuring member(s)) can beinstalled in the measuring stage ST2 provided that such instrument orinstruments perform measurements concerning the exposure process. It isalso allowable that parts of the sensors 400, 500, 600 and the referencemember 300 are provided in the substrate stage ST1.

The measuring stage ST2 arranged on the side of the image plane of theprojection optical system PL has a predetermined area 100 formed so asnot to pollute the liquid LQ. The predetermined area 100 is set to anarea as a part of the upper surface 97 of the measuring stage ST2. Inthis embodiment, the predetermined area 100 is an area of the uppersurface 97, of the measuring stage ST2, except for the areas of theoptical measuring instruments 300, 400, 500 and 600, and is set atsubstantially the center of the upper surface 97 of the measuring stageST2. The size of the predetermined area 100 is set to be larger than theliquid immersion area LR. The predetermined area 100 is substantiallyflush with the upper surfaces 301, 401, 501 and 601 of the opticalmeasuring instruments 300, 400, 500 and 600, respectively. In thisembodiment, the upper surface 97 of the measuring stage ST2 includes theupper surface of the predetermined area 100 and the upper surfaces 301,401, 501 and 601 of the optical measuring instruments 300, 400, 500 and600, respectively.

A predetermined treatment is performed for a partial area of the uppersurface 97 of the measuring stage PT2, and by this predeterminedtreatment, the predetermined area 100 that does not pollute the liquidLQ is formed. Here, the phrase “does not pollute the liquid LQ” means astate in which any elution (entering and mixing) of a contaminant orpollutant (metal, organic ion, inorganic ion, and the like) including aforeign substance from the surface of the predetermined area 100 issuppressed to be not more than a predetermined permissible amount. Inother words, the predetermined area 100 is made of a material which doesnot substantially generate any contaminant in the liquid LQ when thepredetermined area 100 comes into contact with the liquid LQ. Therefore,even when the liquid LQ comes into contact with the predetermined area100, the pollution of the liquid LQ is prevented. The size of thepredetermined area 100 is larger than the liquid immersion area LR, sothat when the liquid immersion area LR of the liquid LQ is formed on theupper surface 97 of the measuring stage ST2 including the predeterminedarea 100, the pollution of the liquid LQ can be prevented by forming theliquid immersion area LR on the inner side of the predetermined area100.

In this embodiment, ceramics is used for the base material forming theupper surface 97 of the measuring stage ST2, and as a treatment forpreventing the pollution of the liquid LQ, a treatment (surfacetreatment) of coating PFA (copolymer of ethylene tetrafluoride (C₂F₄)and perfluoroalkoxyethylene) on the base material (ceramics) forming theupper surface 97 is performed. In the following explanation, thetreatment of coating PFA is referred to as “PFA treatment”.

In this embodiment, the predetermined area 100 is formed on a partialarea of the upper surface 97 of the measuring stage ST2 by performingthe PFA treatment, so that elution (entering and mixing) of acontaminant (metal, organic ion, inorganic ion and the like) including aforeign substance into the liquid LQ from the predetermined area 100 canbe suppressed. Therefore, even when the predetermined area 100 comesinto contact with the liquid LQ, the liquid LQ is prevented from beingpolluted, whereby the influence of the pollution on the liquid LQ isreduced.

The PFA is liquid-repellent (lyophobic) to the liquid (water) LQ, andeven when the liquid immersion area LR is formed on the predeterminedarea 100, the shape, size and the like of the liquid immersion area LRcan be maintained at a desired state by using the liquid immersionmechanism 1. In addition, when an operation for removing (recovering)the liquid LQ from the predetermined area 100 is performed, the liquidLQ can be prevented from remaining on the predetermined area 100.

Here, although a treatment to prevent the pollution of the liquid LQ isperformed for a partial area on the upper surface 97 of the measuringstage ST2, it is also allowable that the treatment to prevent thepollution of the liquid LQ is performed for the entire upper surface 97of the measuring stage ST2 including the upper surfaces 301, 401, 501and 601 of the optical measuring instruments 300, 400, 500 and 600,respectively. In this case, the treatment for the area except for theareas of the optical measuring instruments 300, 400, 500 and 600 and thetreatment for the upper surfaces 301, 401, 501 and 601 of the opticalmeasuring instruments 300, 400, 500 and 600 may be different from eachother. For example, regarding the upper surface 97 of the measuringstage ST2, the PFA treatment is performed for the area on the uppersurface 97 except for the areas of the optical measuring instruments300, 400, 500 and 600, and a treatment of coating a material other thanPFA is performed for the upper surfaces 301, 401, 501 and 601 of theoptical measuring instruments 300, 400, 500 and 600, respectively. As amaterial for coating the upper surfaces 301, 401, 501 and 601 of theoptical measuring instruments 300, 400, 500 and 600, a material whichdoes not pollute the liquid LQ, which is repellent to the liquid LQ, andwhich has optical transparency is preferably used. Those usable as thismaterial include, for example, “Cytop (trademark)” made by Asahi GlassCo., Ltd. Accordingly, even when the liquid immersion area LR isarranged in an area other than the predetermined area 100 of the uppersurface 97 of the measuring stage ST2, the liquid LQ can be preventedfrom being polluted, and the shape, size and the like of the liquidimmersion area LR can be maintained at a desired state. When anoperation for removing the liquid LQ from the upper surface 97 of themeasuring stage ST2 is performed, the liquid LQ can be prevented fromremaining on the upper surface 97. When the upper surface (for example,301) of the optical measuring instrument is subjected to theanti-pollution treatment, at least a part of the upper surface can beused as the predetermined area 100.

The material to be used for the surface treatment of the predeterminedarea 100 (upper surface 97) is not limited to PFA, and any material canbe used provided that the material does not pollute the liquid LQ, andthe material can be arbitrarily selected according to the base materialforming the upper surface 97 of the measuring stage ST2 and theproperties (kind) of the liquid LQ used. Here, although thepredetermined area 100 is formed by performing the surface treatment forthe partial area of the upper surface 97 of the measuring stage ST2, itis also possible that, for example, an opening (concave) is formed on apart of the upper surface 97 of the measuring stage ST2; a plate membermade of PFA or the like is arranged on the inner side of the concave;and the upper surface of this plate member may be set as thepredetermined area 100. Also when the plate member is arranged in theconcave of the upper surface 97 of the measuring stage ST2, it ispreferable that the upper surface of the plate member is flat, and it isdesirable that the upper surface of the plate member is substantiallyflush with the upper surface 97 of the measuring stage ST2 including theupper surfaces 301, 401, 501, and 601 of the respective opticalmeasuring instruments.

FIG. 3 is a drawing showing the liquid immersion area LR of the liquidLQ in a state that the liquid immersion area LR is moving between thesurface of the substrate stage ST1 and the surface of the measuringstage ST2. As shown in FIG. 3, the liquid immersion area LR formed onthe side of the image plane (under or below the first optical elementLS1) of the projection optical system PL is movable between the surfaceof the substrate stage ST1 and the surface of the measuring stage ST2.When moving the liquid immersion area LR, the control unit CONT movesthe substrate stage ST1 and the measuring stage ST2 together in the XYplane within the area including the position immediately below or underthe projection optical system PL by using the stage driving units SD1and SD2 in a state that the substrate stage ST1 and the measuring stageST2 are in proximity to or in contact with each other. By moving thesubstrate stage ST1 and the measuring stage ST2 together, the controlunit CONT can move the liquid immersion area LR between the uppersurface 95 of the substrate stage ST1 and the upper surface 97 of themeasuring stage ST2 while retaining the liquid LQ between the projectionoptical system PL and at least one of the upper surface 95 of thesubstrate stage ST1 and the upper surface 97 of the measuring stage ST2.By doing so, in a state that the optical path space K1 on the side ofthe image plane of the projection optical system PL is filled with theliquid LQ while overflow of the liquid LQ from the gap between thesubstrate stage ST1 and the measuring stage ST2 is restrained orsuppressed, the liquid immersion area LR can be moved between the uppersurface of the substrate stage ST1 and the upper surface of themeasuring stage ST2.

Accordingly, since the liquid immersion area LR of the liquid LQ can bemoved between the upper surface 95 of the substrate stage ST1 and theupper surface 97 of the measuring stage ST2 without the process ofentire recovery of the liquid LQ and the process of re-supply of theliquid LQ, the time from the completion of an exposure operation for asubstrate P on the substrate stage ST1 to the start of an exposureoperation for the next substrate P can be shortened, and the throughputcan be thus improved. On the side of the image plane of the projectionoptical system PL, the liquid LQ is always present, so that an adhesionmark (so-called watermark) of the liquid LQ can be effectivelyprevented.

Next, the liquid supply mechanism 10 and the liquid recovery mechanism20 of the liquid immersion mechanism 1 will be explained with referenceto FIG. 1. The liquid supply mechanism 10 supplies the liquid LQ to theside of the image plane of the projection optical system PL. The liquidsupply mechanism 10 includes a liquid supply unit 11 which is capable offeeding out the liquid LQ and a supply tube 13 whose one end isconnected to the liquid supply unit 11. At an intermediate position ofthe supply tube 13, a valve 13B which opens and closes the flow channelin this supply tube 13 is provided. The operation of the valve 13B iscontrolled by the control unit CONT. The other end of the supply tube 13is connected to the nozzle member 70. Inside the nozzle member 70, aninternal flow channel (supply flow channel) connecting the other end ofthe supply tube 13 and the supply port 12 are formed. In thisembodiment, the liquid supply mechanism 10 supplies pure or purifiedwater, and the liquid supply unit 11 includes a water purifying system16; a temperature adjusting device 17 which adjusts the temperature ofthe liquid (pure water) LQ to be supplied; and the like. Furthermore,the liquid supply unit 11 also includes a tank for accommodating theliquid LQ, a pressurizing pump, a filter unit for removing foreignsubstances in the liquid LQ, and the like. The liquid supply operationof the liquid supply unit 11 is controlled by the control unit CONT. Asthe water purifying device, instead of providing a water purifyingdevice in the exposure apparatus EX, a water purifying device of afactory in which the exposure apparatus EX is installed may be used. Itis not necessarily indispensable that the exposure apparatus body EXincludes all of the tank, pressurizing pump, and filter unit, and thelike, of the liquid supply mechanism 10. Instead, the facilities of afactory, etc., in which the exposure apparatus main body EX is installedmay be used.

In this embodiment, the valve 13B provided in the supply tube 13 adoptsa so-called normal close system which mechanically closes the flowchannel of the supply tube 13 when the drive source (power source) ofthe exposure apparatus EX (control unit CONT) stops due to, for example,a power cut. Thereby, even when an abnormality such as a power cut(electric power failure) occurs, the liquid LQ can be prevented fromleaking from the supply port 12.

The liquid recovery mechanism 20 recovers the liquid LQ on the side ofthe image plane of the projection optical system PL. The liquid recoverymechanism 20 includes a liquid recovery unit 21 capable of recoveringthe liquid LQ and a recovery tube 23 whose one end is connected to theliquid recovery unit 21. At an intermediate position of the recoverytube 23, a valve 23B which opens and closes the flow channel in thisrecovery tube 23 is provided. The operation of the valve 23B iscontrolled by the control unit CONT. The other end of the recovery tube23 is connected to the nozzle member 70. Inside the nozzle member 70, aninternal flow channel (recovery flow channel) which connects the otherend of the recovery tube 23 and the recovery port 22 is formed. Theliquid recovery unit 21 includes a vacuum system (suction unit) such asa vacuum pump, a gas-liquid separator which separates the recoveredliquid LQ from a gas, a tank for accommodating the recovered liquid LQ,and the like. It is not necessarily indispensable that the exposureapparatus body EX includes the vacuum system, the gas-liquid separator,the tank, and the like of the liquid recovery mechanism 20. Instead,facilities of a factory, etc., in which the exposure apparatus body EXis installed may be used.

The supply port 12 for supplying the liquid LQ and the recovery port 22for recovering the liquid LQ are formed in the lower surface 70A of thenozzle member 70. The lower surface 70A of the nozzle member 70 isprovided at a position at which the lower surface 70A can face or can beopposite to the upper surface of the substrate P, the upper surface 95of the substrate stage ST1, and the upper surface 97 of the measuringstage ST2. The nozzle member 70 is an annular member provided so as tosurround the side surfaces of the first optical element LS1, and thesupply port 12 is provided as a plurality of supply ports 12 at thelower surface 70A of the nozzle member 70 so as to surround the firstoptical element LS1 of the projection optical system PL (the opticalaxis AX of the projection optical system PL). At the lower surface 70Aof the nozzle member 70, the recovery port 22 is arranged at a positionoutwardly away, than each of the supply ports 12, from the first opticalelement LS1 so as to surround the first optical element LS1 and each ofthe supply ports 12.

The control unit CONT locally forms a liquid immersion area LR of theliquid LQ on the substrate P by supplying a predetermined amount of theliquid LQ to the substrate P by using the liquid supply mechanism 10,and by recovering a predetermined amount of the liquid LQ from thesurface of the substrate P by using the liquid recovery mechanism 20.When forming the liquid immersion area LR of the liquid LQ, the controlunit CONT drives each of the liquid supply unit 11 and the liquidrecovery unit 21. When the liquid LQ is fed out from the liquid supplyunit 11 under control by the control unit CONT, the liquid LQ fed outfrom the liquid supply unit 11 flows through the supply tube 13, and isthen supplied to the side of the image plane of the projection opticalsystem PL from the supply ports 12 via the supply flow channel of thenozzle member 70. When the liquid recovery unit 21 is driven undercontrol by the control unit CONT, the liquid LQ on the side of the imageplane of the projection optical system PL flows into the recovery flowchannel of the nozzle member 70 through the recovery ports 22, and isrecovered by the liquid recovery unit 21 after flowing through therecovery tube 23.

In this embodiment, the liquid LQ recovered by the liquid recoverymechanism 20 is returned to the liquid supply unit 11 of the liquidsupply mechanism 10. Namely, the exposure apparatus EX of thisembodiment includes a circulation system which circulates the liquid LQbetween the liquid supply mechanism 10 and the liquid recovery mechanism20. The liquid LQ returned to the liquid supply unit 11 of the liquidsupply mechanism 10 is purified in the water purifying system 16, andthen supplied again to the side of the image plane (surface of thesubstrate P) of the projection optical system PL. All of the liquid LQrecovered by the liquid recovery mechanism 20 may be returned to theliquid supply mechanism 10, or a part of the recovered liquid LQ may bereturned to the liquid supply mechanism 10. Alternatively, instead ofreturning the liquid LQ recovered by the liquid recovery mechanism 20 tothe liquid supply mechanism 10, the liquid LQ, supplied from anothersupply source or tap water, may be purified by the water purifyingsystem 16 and then may be supplied to the side of the image plane of theprojection optical system PL. The structure of the liquid immersionmechanism 1 including the nozzle member 70, and the like is not limitedto the above-described structure, and the structures described in, forexample, European Patent Application Publication No. 1420298, andInternational Patent Application Publication Nos. 2004/055803,2004/057589, 2004/057590, and 2005/029559 may be also adopted.

Next, the liquid supply unit 11 will be explained with reference to FIG.4. FIG. 4 shows the construction of the liquid supply unit 1 in detail.The liquid supply unit 11 includes a water purifying system 16 and atemperature adjusting device 17 which adjusts the temperature of theliquid LQ produced by the water purifying system 16. The water purifyingsystem 16 includes a water purifying unit 161 which produces pure waterwith a predetermined purity by purifying water containing suspendedsolids and impurities, and an ultrapure water-producing unit 162 whichproduces highly-pure water (ultrapure water) by further removingimpurities from the pure water produced by the water purifying unit 16.The water purifying unit 161 (or ultrapure water-producing unit 162)includes a liquid reforming member such as an ion exchange membrane or aparticle filter, and a liquid reforming unit such as an ultravioletirradiation unit (UV lamp), and by the liquid reforming member andliquid reforming unit, a specific resistance, an amount of foreignsubstances (particles and bubbles), total organic carbon, an amount ofbacteria, and the like of the liquid are adjusted to desired values.

As described above, the liquid LQ recovered by the liquid recoverymechanism 20 is returned to the liquid supply unit 11 of the liquidsupply mechanism 10. Specifically, the liquid LQ recovered by the liquidrecovery mechanism 20 is supplied to the water purifying system 16(water purifying unit 161) of the liquid supply unit 11 via a returntube 18. In the return tube 18, a first valve 18B which opens and closesthe flow channel in the return tube 18 is provided. The water purifyingsystem 16 purifies the liquid LQ, returned via the return tube 18, byusing the liquid reforming member and the liquid reforming unit, andthen supplies the liquid LQ to the temperature adjusting device 17. Tothe water purifying system 16 (water purifying unit 161) of the liquidsupply unit 11, a functional fluid supply unit 120 is connected via asupply tube 19. The functional fluid supply unit 120 can supply afunctional fluid LK having a predetermined function different from thatof the liquid LQ for forming the liquid immersion area LR. In thisembodiment, the functional fluid supply unit 120 supplies a functionalfluid LK that has a cleaning effect or a sterilization effect, or afunctional fluid LK having both of these effects. As the functionalfluid LK, for example, ozone water, a solution or a water-solubleorganic solvent containing surfactant, antibacterial agent,disinfectant, sterilizer and the like can be used. In this embodiment,as the functional fluid LK, hydrogen peroxide solution is used. In thesupply tube 19, a second valve 19B which opens and closes the flowchannel in the supply tube 19 is provided. The control unit CONT stopsthe supply of the functional fluid LK by closing the flow channel in thesupply tube 19 by actuating the second valve 19B when supplying theliquid LQ by opening the flow channel in the return tube 18 by actuatingthe first valve 18B. On the other hand, the control unit CONT stops thesupply of the liquid LQ by closing the flow channel in the return tube18 by actuating the first valve 18B when supplying the functional fluidLK by opening the flow channel in the supply tube 19 by actuating thesecond valve 19B.

The temperature adjusting device 17 adjusts the temperature of theliquid (pure water) LQ which is produced by the water purifying system16 and supplied to the supply tube 13, and one end of the temperatureadjusting device is connected to the water purifying system 16(ultrapure water-producing unit 162) and the other end of thetemperature adjusting device 17 is connected to the supply tube 13, andafter adjusting the temperature of the liquid LQ produced by the waterpurifying system 16, the temperature adjusting device feeds thetemperature-adjusted liquid LQ to the supply tube 13. The temperatureadjusting device 17 includes a rough temperature adjusting unit 171which roughly adjusts the temperature of the liquid LQ supplied from theultrapure water-producing unit 162 of the water purifying system 16, aflow controller 172 called a mass flow controller which is provided on adownstream side of the flow channel (on a side of the supply tube 13) ofthe rough temperature adjusting device 171 and controls an amount perunit time of the liquid LQ to be flown to the side of the supply tube13, a degassing unit 173 for lowering the dissolved gas concentration(dissolved oxygen concentration, dissolved nitrogen concentration) inthe liquid LQ which has passed through the flow controller 172, a filter174 for removing foreign substances (fine particles, air bubbles) in theliquid LQ degassed by the degassing unit 173, and a fine temperatureadjusting unit 175 which finely adjusts the temperature of the liquid LQwhich has passed through the filter 174.

The rough temperature adjusting unit 171 adjusts the temperature of theliquid LQ fed from the ultrapure water-producing unit 162 at an accuracyas rough as ±0.1° C. with respect to a target temperature (for example,23° C.). The flow controller 172 is arranged between the roughtemperature adjusting unit 171 and the degassing unit 173, and controlsthe flow rate per unit time of the liquid LQ, temperature-adjusted bythe rough temperature adjusting unit 171, to the side of the degassingunit 173.

The degassing unit 173 is arranged between the rough temperatureadjusting unit 171 and the fine temperature adjusting unit 175, morespecifically, between the flow controller 172 and the filter 174, anddegasses the liquid LQ fed from the flow controller 172 to lower thedissolved gas concentration (dissolved oxygen concentration, dissolvednitrogen concentration) in the liquid LQ. As the degassing unit 173, apublicly-known degassing unit such as a decompressor which performsdegassing by reducing the pressure of the supplied liquid LQ can beused. In addition, a device including a degassing filter which separatesgas from liquid in the liquid LQ by using a filter such as ahollow-fiber membrane filter and removes the separated gas component byusing a vacuum system, or a device including a degassing pump whichseparates gas from liquid of the liquid LQ by using a centrifugal forceand removes the separated gas component by using a vacuum system, canalso be used. The degassing unit 173 adjusts the dissolved gasconcentration to a desired value by using a liquid reforming memberincluding the degassing filter and a liquid reforming unit including thedegassing pump.

The filter 174 is arranged between the rough temperature adjusting unit171 and the fine temperature adjusting unit 175, more specifically,between the degassing unit 173 and the fine temperature adjusting unit175, and removes foreign substances in the liquid LQ fed from thedegassing unit 173. When the liquid LQ passes through the flowcontroller 172 and the degassing unit 173, there is a possibility that aslight amount of foreign substances (particles) is mixed with the liquidLQ. However, by providing the filter 174 on the downstream side (side ofthe supply tube 13) of the flow controller 172 and the degassing unit173, the foreign substances can be removed by this filter 174. As thefilter 174, a publicly-known filter such as a hollow fiber membranefilter or a particle filter can be used. The filter 174 including aliquid reforming member such as the particle filter adjusts the amountof foreign substances (particles, air bubbles) in the liquid to not morethan a permissible value.

The fine temperature adjusting unit 175 is arranged between the roughtemperature adjusting unit 171 and the supply tube 13, morespecifically, between the filter 174 and the supply tube 13, and adjuststhe temperature of the liquid LQ with high accuracy or precision. Forexample, the fine temperature adjusting unit 175 finely adjusts thetemperature (temperature stability and temperature uniformity) of theliquid LQ fed from the filter 174 at an accuracy as high as ±0.01° C. to±0.001° C. with respect to a target temperature. In this embodiment,among the plurality of units or devices constructing the temperatureadjusting device 17, the fine temperature adjusting unit 175 is arrangedat a position most closely to the substrate P which is an object to besupplied with the liquid LQ. Accordingly, the liquid LQ which is highlyaccurately adjusted in temperature can be supplied to the surface of thesubstrate P.

It is preferable that the filter 174 is arranged between the roughtemperature adjusting unit 171 and the fine temperature adjusting unit175 in the temperature adjusting device 17. However, the filter 174 maybe arranged at another position in the temperature adjusting device 17,or arranged outside the temperature adjusting device 17.

As described above, each of the water purifying unit 161, the ultrapurewater-producing unit 162, the degassing unit 173, the filter 174, andthe like has a liquid reforming member and a liquid reforming unit, andfunctions as an adjusting unit for adjusting at least one of theproperty and the components of the liquid LQ. These units 161, 162, 173,174 and the like are provided in the liquid supply mechanism 10 atpredetermined positions, respectively, in the flow channel in which theliquid LQ flows. In this embodiment, one liquid supply unit 11 isarranged (see FIG. 1) for one exposure apparatus EX. However, theconstruction is not limited to that as described above, and it is alsopossible that a plurality of exposure apparatuses EX share one liquidsupply unit 11. This reduces the area occupied by the liquid supply unit11 (footprint). Alternatively, it is also possible that the waterpurifying system 16 and the temperature adjusting device 17 constructingthe liquid supply unit 11 are divided and the water purifying system 16is shared by a plurality of exposure apparatuses EX and the temperatureadjusting device 17 may be provided for each of the exposure apparatusesEX. This reduces the footprint and enables temperature control for eachof the exposure apparatuses EX. Furthermore, in the case describedabove, by arranging the liquid supply unit 11 or water purifying system16, shared by a plurality of exposure apparatuses EX, on a floor (forexample, under floor) different from the floor on which the exposureapparatuses EX are placed (installed), the space of the clean room inwhich the exposure apparatuses EX are installed can be more effectivelyutilized.

Next, the measuring unit 60 will be explained with reference to FIG. 5.The measuring unit 60 measures at least one of the property and thecomponents of the liquid LQ filled in a space between the projectionoptical system PL and an object arranged on the side of the image planeof the projection optical system PL. As described above, since theliquid LQ in this embodiment is water, at least one of the property andcomponents of the liquid LQ will be arbitrarily referred to as “waterquality” in the following explanation.

The measuring unit 60 is provided at an intermediate position in therecovery tube 23, and measures the liquid LQ recovered by the liquidrecovery mechanism 20. The liquid recovery mechanism 20 recovers theliquid LQ, filled in the space between the projection optical system PLand the object, through the recovery ports 22 of the nozzle member 70.Accordingly, the measuring unit 60 measures the water quality (at leastone of the property and the components) of the liquid LQ which has beenrecovered through the recovery ports 22 of the nozzle member 70 and isflowing in the recovery tube 23, that is, the liquid LQ filled in thespace between the projection optical system PL and the object.

As explained with reference to FIG. 3, the liquid immersion area LR ofthe liquid LQ is movable between the surface of the substrate stage ST1and the surface of the measuring stage ST2. When the water quality ofthe liquid LQ is measured with the measuring unit 60, the control unitCONT supplies and recovers the liquid LQ by using the liquid immersionmechanism 1 in a state that the projection optical system PL is made toface or to be opposite to the measuring stage ST2, and fills the opticalpath space K1 between the projection optical system PL and the measuringstage ST2 with the liquid LQ. More specifically, when the water qualityof the liquid LQ is measured with the measuring unit 60, the controlunit CONT fills the liquid LQ in the space between the projectionoptical system PL and the predetermined area 100 of the upper surface 97of the measuring stage ST2. The measuring unit 60 measures the waterquality of the liquid LQ filled in the space between the projectionoptical system PL and the predetermined area 100 of the measuring stageST2.

As explained above, the predetermined area 100 of the measuring stageST2 is formed so as not to pollute the liquid LQ. Therefore, themeasuring unit 60 measures the liquid LQ which is filled in the spacebetween the projection optical system PL and the predetermined area 100and is prevented from being polluted. Therefore, the measuring unit 60can accurately measure the true water quality of the liquid LQ filled inthe optical path space K1 on the side of the image plane of theprojection optical system PL (liquid LQ supplied to the optical pathspace K1). The result of measurement by the measuring unit 60 isoutputted to the control unit CONT. The control unit CONT can judgewhether the state (water quality) of the liquid LQ filled in the spacebetween the projection optical system PL and the predetermined area 100of the measuring stage ST2 is in a desired state based on the result ofmeasurement by the measuring unit 60.

For example, a consideration is given to a case in which the liquid LQis filled in a space between the projection optical system PL and amember which may generate a pollutant, and in which measuring unit 60measures the liquid LQ. The member which may generate a pollutantincludes a member (upper surface of stage) which has not been subjectedto the above-described surface treatment (PFA treatment, or the like),or a substrate P or the like coated with a photosensitive material. Inthis case, even when it is judged that the liquid LQ has been pollutedbased on the result of measurement by the measuring unit 60, it isdifficult to identify the cause of the pollution (defect or trouble) ofthe liquid LQ. Namely, in this case, possible causes of the pollution(defect) of the liquid LQ are at least two of a failure of the waterpurifying system 161 of the liquid supply unit 11 and an influence froma pollutant generated from the member. In this case, it is difficult toidentify the cause of the pollution (defect) of the liquid LQ based onthe result of measurement by the measuring unit 60. When the cause ofpollution (defect) of the liquid LQ cannot be identified, it isdifficult to take a measure for eliminating the defect or take a measurefor making the liquid LQ to be in a desired state (clean state). In thisembodiment, the liquid LQ is measured by forming the liquid immersionarea LR of the liquid LQ on the predetermined area 100 formed so as notto pollute the liquid LQ. Accordingly, the control unit CONT canaccurately obtain the true state (water quality) of the liquid LQ basedon the result of measurement by the measuring unit 60, and when thecontrol unit judges that the measured liquid LQ is polluted, it canjudge that the cause of the pollution is, for example, a failure of thewater purifying unit 161 of the liquid supply unit 11. Therefore, forexample, when performing maintenance of the water purifying unit 161, aproper measure (countermeasure) for making the liquid LQ to be in adesired state can be taken.

In addition, instead of setting the measuring position at anintermediate position of the recovery tube 23 as in this embodiment, acase will be considered in which, for example, a measuring position formeasuring the liquid LQ is provided at an intermediate position of thesupply tube 13 and the measuring unit 60 measures water quality of theliquid LQ at this measuring position. By measuring the liquid LQ at themeasuring position provided in at the intermediate position of thesupply tube 13, the liquid LQ can be measured without being influencedby a member that may generate a pollutant as described above. However,if the flow channel in a predetermined section between the measuringposition provided at the intermediate position of the supply tube 13 andthe supply ports 12 of the nozzle member 70 is polluted due to somereason, the liquid LQ to be supplied to the optical path space K1through the supply ports 12 may be polluted when flowing in the flowchannel in the predetermined section. However, since the measuringposition is provided on a upstream side of the predetermined section,there occurs a problem such that the measuring unit 60 cannot measurethe pollution of the liquid LQ. Then, even when the polluted liquid LQis actually supplied to the optical path space K1, the measuring unit 60cannot grasp (measure) the pollution of the liquid LQ supplied to theoptical path space K1. In this case, not only that a measure(countermeasure) for maintaining the liquid LQ at a desired state cannotbe taken, but also it becomes difficult to identify the cause fordegradation of the exposure accuracy and measurement accuracy.Consequently, the measurement process by the optical measuringinstruments 300, 400, 500, and 60, and the exposure process of thesubstrate P are performed via the polluted liquid LQ, and thus themeasurement accuracy and the exposure accuracy via the liquid LQdegrades. In this embodiment, the measuring position is set on adownstream side of the optical path space K1, more specifically, at anintermediate position in the recovery tube 23, so that theabove-described problem can be prevented.

In this embodiment, since water is used as the liquid LQ, PFA treatmentis performed for the predetermined area 100. However, when the liquid LQis a liquid other than water, there is a possibility that foreignsubstance or substances are eluted (mixed) into the liquid LQ from thepredetermined area 100. In this case, as described above, a treatmentwhich prevents pollution of the liquid is performed for the measuringstage ST2, according to the property (kind) of the liquid to be used.

Items concerning the property and components (water quality or liquidquality, or the state of the liquid) of the liquid LQ to be measured bythe measuring unit 60 are determined by considering the influencesthereof on the exposure accuracy and measurement accuracy of theexposure apparatus EX, or influences on the exposure apparatus EXitself. Table 1 indicates an example of items concerning the propertyand components of the liquid LQ and the influences thereof on theexposure accuracy of the exposure apparatus EX or the influences thereofon the exposure apparatus EX itself. As shown in Table 1, the items ofthe property and components of the liquid LQ include physical propertiessuch as specific resistance; metal ions; total organic carbon (TOC);particles/bubbles; an inclusion such as bacteria (foreign substance orpollutant); dissolved gases such as dissolved oxygen (DO), dissolvednitrogen (DN); and the like. On the other hand, the items concerning theinfluences on the exposure accuracy of the exposure apparatus EX or theinfluences on the exposure apparatus EX itself include fogging of a lens(especially, the optical element LS1); watermark (adhesion remaining asa result of solidification of an impurity in the liquid due to theevaporation of the liquid LQ); degradation of optical property due to achange in refractive index or light scattering; influence on resistprocess (resist pattern formation); rusting of the respective members;and the like. Table 1 summarizes these to indicate which of the items ofproperty or components influences how much and on which performance, andin Table 1, items expected to have grave influences are marked by a “◯”(circle). The items of the property and components of the liquid LQ tobe measured by the measuring unit 60 are selected as appropriate fromTable 1 based on the influences thereof on the exposure accuracy andmeasurement accuracy of the exposure apparatus EX and the influencesthereof on the exposure apparatus EX itself. It is allowable that all ofthe items are measured, and that items concerning the property, and thatcomponents not shown in Table 1 may be measured.

TABLE 1 Influence Lens Drainage Resist fogging Watermark Opticalproperty pollution process Rusting Property and Specific resistance ∘ ∘∘ ∘ ∘ components Metal ion ∘ ∘ ∘ of liquid Total organic ∘ ∘ ∘ ∘ carbon(TOC) Particles/bubbles ∘ ∘ ∘ ∘ Bacteria ∘ ∘ ∘ ∘ Dissolved oxygen ∘ ∘ ∘(DO) Dissolved nitrogen ∘ (DN) Silica ∘ ∘ ∘ Organic Si ∘ ∘ ∘ ∘ Negativeion ∘ ∘ ∘ ∘ ∘ Siloxane series, ∘ ∘ ∘ ∘ ∘ CxHy series Phthalate ester ∘ ∘∘ ∘ ∘ Cl ∘ ∘ ∘ ∘ ∘ PO₄, SO₄, NOx (PAG) ∘ ∘ ∘ ∘ ∘ Ammonia, amines ∘ ∘ ∘ ∘∘ Base resin ∘ ∘ ∘ ∘ ∘ Carboxylic acids ∘ ∘ ∘ ∘ ∘ (lactic acid, aceticacid, formic acid)

For measuring the items selected from the above-described viewpoints,the measuring unit 60 has a plurality of measuring instruments. Forexample, the measuring unit 60 can include, as the measuringinstruments, a specific resistance meter for measuring the specificresistance, a TOC meter for measuring the total organic carbon, aparticle counter for measuring foreign substances including particlesand bubbles, a DO meter for measuring dissolved oxygen (dissolved oxygenconcentration), a DN meter for measuring dissolved nitrogen (dissolvednitrogen concentration), a silica meter for measuring silicaconcentration, an analyzer capable of analyzing the kinds and amounts ofbacteria, and the like. In this embodiment, total organic carbon,particles/bubbles, dissolved oxygen, specific resistance are selected asan example of measuring items, and as shown in FIG. 5, the measuringunit 60 includes a TOC meter 61 for measuring total organic carbon, aparticle counter 62 for measuring foreign substances including particlesand bubbles, and a dissolved oxygen meter (DO meter) 63 for measuringdissolved oxygen, and a specific resistance meter 64.

As shown in FIG. 5, the TOC meter 61 is connected to a branched tube(branched flow channel) 61K branched from the recovery tube (recoveryflow channel) 23 connected to the recovery ports 22, at an intermediateportion of the recovery tube 23. In the recovery tube 23, the liquid LQrecovered through the recovery ports 22 flows. The liquid LQ flowing inthe recovery tube 23 is the liquid filled in the space between theprojection optical system PL and the predetermined area 100 of themeasuring stage ST2. A part of the liquid LQ flowing in the recoverytube 23 is recovered by the liquid recovery unit 21, and the remainingpart flows through the branched tube 61K and flows into the TOC meter61. The TOC meter 61 measures total organic carbon (TOC) in the liquidLQ flowing in the branched flow channel formed by the branched tube 61K.Similarly, the particle counter 62, the dissolved oxygen meter 63, andthe specific resistance meter 64 are connected to branched tubes 62K,63K, and 64K, respectively, branched from the recovery tube 23 atintermediate positions thereof, and measures foreign substances(particles or bubbles), dissolved oxygen, and specific resistance,respectively, in the liquid LQ flowing in branched flow channels formedby the branched tubes 62K, 63K, and 64K. The silica meter and bacteriaanalyzer are also connectable to the branched tubes branched from therecovery tube 23 at an intermediate portion thereof.

As described above, since the measuring items of the measuring unit 60can be selected as appropriate, the measuring unit 60 can include anyone or a plurality of the measuring instruments 61 to 64.

In this embodiment, the branched tubes 61K to 64K form branched flowchannels independent from each other, and to each of the branched flowchannels independent from each other, one of the measuring instruments61 to 64 is connected. Namely, the plurality of measuring instruments 61to 64 are connected parallel to the recovery tube 23 via the branchedtubes 61K to 64K, respectively. Depending on the constructions of themeasuring instruments, it is also allowable that, for example, aplurality of measuring instruments are connected in series to therecovery tube 23 so that the liquid LQ branched from the recovery tube23 is measured by a first measuring instrument, and the liquid LQ thathas passed through the first measuring instrument is measured by asecond measuring instrument. Depending on the number and position of thebranched tubes (branched points), the possibility that foreignsubstances (particles) are generated is high. Accordingly, the numberand positions of the branched tubes are set by considering thepossibility of generation of foreign substances.

A sampling position for sampling a part of the liquid LQ may be set atan intermediate position in the recovery tube 23. For example, toidentify the kinds of the metal ions contained or present in the liquidLQ, it is possible to sample the liquid LQ to identify the kinds of themetal ions by using an analyzer provided separately from the exposureapparatus EX. This makes it possible to take a proper measure accordingto the identified metal ions. In addition, to measure impuritiescontained in the liquid LQ, it is also possible to sample the liquid LQto measure the amount of total evaporated residue in the liquid LQ by atotal evaporated residue meter provided separately from the exposureapparatus EX.

In this embodiment, the measuring unit 60 measures the water quality ofthe liquid LQ flowing in the branched flow channels branched from therecovery flow channel formed by the recovery tube 23, at theintermediate positions in the recovery flow channel. Since this makes itpossible that the liquid LQ is always supplied to the measuring unit 60,the control unit CONT can satisfactorily measure the water quality ofthe liquid LQ by performing the same operations as in the liquidimmersion exposure operation, that is, a liquid supply operation throughthe supply ports 12 and the liquid recovery operation through therecovery ports 22 without executing special operations.

Next, a method for exposing the image of the pattern of the mask M onthe substrate P by using the exposure apparatus EX constructed asdescribed above will be explained with reference to the flowchart ofFIG. 6. In this embodiment, a plurality of substrates P are successivelyexposed. More specifically, the plurality of substrates P are managed bylot, and the exposure apparatus EX performs exposure for each of thelots in order.

The control unit CONT moves the substrate stage ST1 to a predeterminedsubstrate exchange position by using the substrate stage driving unitSD1. At the substrate exchange position, by a conveyance system that isnot shown, operations for unloading a substrate P after being exposedfrom the substrate stage ST1 and loading a substrate P before beingexposed are performed. Of course, when no substrate P after beingexposed is present on the substrate stage ST1, any unloading of asubstrate P is not performed, and only loading of a substrate P beforebeing exposed is performed. There are cases in which, at the substrateexchange position, only the unloading of a substrate P after beingexposed is performed and the loading of a substrate P before beingexposed is not performed. In the following explanation, an operation forperforming, at least one of the loading of a substrate P before beingexposed to the substrate stage ST1 and the unloading of a substrate Pafter being exposed from the substrate stage ST1, is referred to as“substrate exchange operation” as appropriate.

In this embodiment, during the substrate exchange operation on thesubstrate stage ST1, a measurement process using the measuring stage ST2is performed. The control unit CONT starts a predetermined measurementprocess using the measuring stage ST2 while performing at least a partof the substrate exchange operation on the substrate stage ST1 (StepSA1).

The control unit CONT supplies and recovers the liquid LQ by using theliquid immersion mechanism 1 in a state that the lower surface LSA ofthe projection optical system PL is made to face or to be opposite tothe predetermined area 100 of the upper surface 97 of the measuringstage ST2, that is, the predetermined area 100 is arranged at a positionat which the substrate P is set for exposure, and fills the liquid LQ ina space between the projection optical system PL and the predeterminedarea 100 of the measuring stage ST2. Then, the control unit CONTmeasures the water quality of the liquid LQ in the space between theprojection optical system PL and the predetermined area 100 of themeasuring stage ST2 by using the measuring unit 60. As described above,the measuring unit 60 measures the liquid LQ of which pollution issuppressed. The result of measurement by the measuring unit 60 isoutputted to the control unit CONT. The control unit CONT stores theresult of measurement made by the measuring unit 60 in the memory MRY(Step SA2).

In this embodiment, the control unit CONT stores the result ofmeasurement of the liquid LQ arranged on the predetermined area 100,performed by the measuring unit 60, in the memory MRY by associating theresult with elapse of time. For example, by providing a valve sensorcapable of detecting whether the valve 13B closes the flow channel ofthe supply tube 13, and by providing the control unit CONT with a timerfunction, the control unit CONT can measure the elapsed time from thetime of detection that the valve 13B opened the flow channel of thesupply tube 13, that is, the elapsed time from the start of the supplyof the liquid LQ by the liquid supply mechanism 10. Accordingly, thecontrol unit CONT can store the result of measurement made by themeasuring unit 60 in the memory MRY by associating the result with theelapse of time by defining the time of start of the supply of the liquidLQ, to the side of the image plane of the projection optical system PLby the liquid supply mechanism 10, as a measurement start point(reference). The control unit CONT sets the time when the control unitCONT detects the valve 13B closed the flow channel 13. Namely, thecontrol unit CONT sets the time, when the supply of the liquid LQ to theside of the image plane of the projection optical system PL by theliquid supply mechanism 10 is stopped, as the measurement start point(reference). In the following explanation, information on the result ofmeasurement, by the measuring unit 60, of water quality of the liquid LQfilled in the space between the projection optical system PL and thepredetermined area 100 of the measuring stage ST2, which is stored bybeing associated with elapse of time, will be referred to as “first loginformation” as appropriate.

In this embodiment, during a substrate exchange operation on thesubstrate stage ST1 after a plurality of substrates P have beensuccessively exposed, a liquid immersion area LR of the liquid LQ isformed on the predetermined area 100 on the measuring stage ST2, and ameasuring operation for the liquid LQ is performed by the measuring unit60. The measurement process for the liquid LQ by the measuring unit 60is performed every exchange of the substrate P on the substrate stageST1, or every exposure process of a predetermined number of substratesP, or for each lot of the substrates P. When a plurality of substrates Pare successively exposed, the control unit CONT stores the results ofmeasurements by the measuring unit 60 in the memory MRY by associatingthe results with substrates P. In the following explanation, when aplurality of substrates P are successively exposed, information on theresults of measurements made by the measuring unit 60 about waterquality of the liquid LQ filled in the space between the projectionoptical system PL and the predetermined area 100 of the measuring stageST2, which is stored by being associated with the substrates P, isreferred to as “second log information” as appropriate.

The control unit CONT can indicate (inform) the results of measurementsmade by the measuring unit 60 by the reporting unit INF including adisplay device.

The control unit CONT judges whether or not the results of measurementsby the measuring unit 60 are abnormal (step SA3). The control unit CONTcontrols the operations of the exposure apparatus EX based on the resultof judgment.

Abnormal results of measurements made by the measuring unit 60 include asituation that the state of the liquid LQ (water quality) is not in adesired state but is abnormal, a measured value of each of therespective items (TOC, foreign substance, dissolved gas concentration,silica concentration, bacteria, specific resistance, and the like)measured by the measuring unit 60 is not less than a permissible valueset in advance, and exposure process and measurement process through theliquid LQ cannot be performed in a desired state.

Here, in the following explanation, a permissible value concerning waterquality of the liquid LQ filled in the space between the projectionoptical system PL and the predetermined area 100 will be referred to as“first permissible value” as appropriate. The first permissible valuemeans a permissible value concerning water quality of the liquid LQ thatis not substantially influenced by the object (herein, the predeterminedarea 100) arranged on the side of the image plane of the projectionoptical system PL.

The first permissible value can be obtained in advance by, for example,an experiment or simulation. When the measured value concerning thewater quality of the liquid LQ is not more than the first permissiblevalue, the exposure process and measurement process through the liquidLQ can be performed in a desired state.

For example, if the value of the total organic carbon in the liquid LQis greater (abnormal) than the first permissible value (for example, 1.0ppb), there is a possibility that the transmittance of the liquid LQ hasbeen lowered. In this case, the measurement accuracies of the opticalmeasuring instruments 300, 400, 500, and 600 through the liquid LQ aredegraded. Alternatively, the exposure accuracy of the substrate Pthrough the liquid LQ is degraded.

If the amount of foreign substances including particles or bubbles inthe liquid LQ is greater (abnormal) than the first permissible value,there is high possibility that the measurement accuracies of the opticalmeasuring instruments 300, 400, 500, and 600 through the liquid LQ aredegraded or the pattern transferred to the substrate P through theliquid LQ becomes defective.

If the value of dissolved gases (dissolved gas concentration) includingdissolved oxygen and dissolved nitrogen in the liquid LQ is greater(abnormal) than the first permissible value, for example, when theliquid LQ supplied to the substrate P through the supply ports 12 isreleased to the atmosphere, there is high possibility that bubbles aregenerated in the liquid LQ due to the dissolved gases in the liquid LQ.If bubbles are generated in the liquid LQ, similarly to the explanationgiven above, there is high possibility that the measurement accuraciesof the optical measuring instruments 300, 400, 500, and 600 are degradedand the pattern transferred to the substrate P becomes defective.

If the amount of bacteria is great (abnormal), the liquid LQ is pollutedand lowered in transmittance. Further, when the amount of bacteria isgreat, there is a problem or inconvenience such that the members whichcome into contact with the liquid LQ (the nozzle member 70, the opticalelement LS1, the measuring stage ST2, the substrate stage ST1, thesupply tube 13, the recovery tube 23, and the like) are polluted,thereby spreading the pollution.

If the specific resistance of the liquid LQ is smaller (abnormal) thanthe first permissible value (for example, 18.2 MΩ·cm at 25° C.), thereis a possibility that the liquid LQ contains a large amount of metalions such as sodium ions, or the like. If the liquid immersion area LRis formed on the substrate P by the liquid LQ containing a large amountof the metal ions, there is a possibility that the metal ions in theliquid LQ infiltrate into the photosensitive material on the substrate Pand adhere to the device pattern (wiring pattern) that has already beenformed under the photosensitive material, thereby causing inconveniencesuch as a malfunction of the device.

The control unit CONT controls the operations of the exposure apparatusEX based on the first permissible value set in advance concerning thewater quality of the liquid LQ and the result of measurement by themeasuring unit 60.

At Step SA3, when it is judged that the result of measurement by themeasuring unit 60 is not abnormal, that is, the water quality of theliquid LQ is not abnormal, the control unit CONT fills the liquid LQ inthe space between the first optical element LS1 of the projectionoptical system PL and the upper surface 97 of the measuring stage ST2 byusing the liquid immersion mechanism 1, and performs a measuringoperation using at least one of the optical measuring instruments 300,400, 500, and 600 (Step SA4). The liquid LQ filled in the space betweenthe projection optical system PL and the upper surfaces 301, 401, 501,and 601 of the optical measuring instruments 300, 400, 500, and 600,respectively, is the liquid LQ judged (confirmed) as being in a desiredstate without abnormality in water quality at Step SA3. Therefore, themeasurement process using the optical measuring instrument through theliquid LQ in the desired state can be satisfactorily performed.

The measuring operation using the optical measuring instrument can beexemplified by a baseline measurement. Specifically, the control unitCONT simultaneously detects the first reference mark MFM on thereference member 300 provided in the measuring stage ST2 and acorresponding mask alignment mark on the mask M by using theabove-described mask alignment system, and detects the positionalrelationship between the first reference mark MFM and the correspondingmask alignment mark. Simultaneously, or before or after thesedetections, the control unit CONT detects the positional relationshipbetween a detection reference position of the substrate alignment systemand the second reference mark PFM by detecting the second reference markPFM on the reference member 300 by the substrate alignment system. Asdescribed above, when the first reference mark MFM is measured, theliquid immersion area LR is formed on the first reference mark MFM, andthe measurement process through the liquid LQ is performed. On the otherhand, when the second reference mark PFM is measured, the liquidimmersion area LR is not formed on the second reference mark PFM, andthe measurement process is performed not through the liquid LQ. Then,the control unit CONT obtains a distance between the projection positionof the pattern of the mask M by the projection optical system PL and thedetection reference position of the substrate alignment system, namely,baseline information of the substrate alignment system, based on thepositional relationship between the first reference mark MFM and thecorresponding mask alignment mark, the positional relationship betweenthe detection reference position of the substrate alignment system andthe second reference mark PFM, and the known positional relationshipbetween the first reference mark MFM and the second reference mark PFM.

The measuring operation using the optical measuring instrument is notlimited to the above-described baseline measurement, and at least one ofilluminance unevenness measurement, spatial image measurement,illuminance measurement and the like using the optical measuringinstruments 400, 500, and 600 provided on the measuring stage ST2 can beperformed as the measuring operation. The control unit CONT reflects theresults of measurements made by the optical measuring instruments 400,500, and 600 on a subsequent exposure process of the substrate P byperforming, for example, various corrections such as calibration of theprojection optical system PL. In the case of the measurement processusing the optical measuring instruments 400, 500, and 600, the controlunit CONT fills the liquid LQ in the space between the first opticalelement LS1 of the projection optical system PL and the upper surface 97of the measuring stage ST2 to perform the measurement process throughthe liquid LQ.

On the other hand, at Step SA3, when the result of measurement by themeasuring unit 60 is judged as abnormal, that is, water quality of theliquid LQ is judged as abnormal, the control unit CONT does not performthe measuring operation using the optical measuring instruments, andreports (informs) the result of measurement made by the measuring unit60 by using the reporting unit INF (Step SA14). For example, the controlunit CONT can indicate information on variation amounts of TOC anddissolved gas concentration in the liquid LQ with the elapse of time, bythe reporting unit INF including a display device. Also, when the resultof measurement by the measuring unit 60 is judged as abnormal, thecontrol unit CONT can inform that the result of measurement is abnormalby the reporting unit in such a way that an alarm (warning) is issued bythe reporting unit INF. Further, when the result of measurement by themeasuring unit 60 is judged as abnormal, the control unit CONT can stopthe supply of the liquid LQ by the liquid supply mechanism 10. It isalso allowable to recover the liquid LQ remaining on the measuring stageST2 by using the liquid recovery mechanism 20 including the nozzlemember 70.

As described above, the liquid supply unit 11 includes a liquidreforming member, a liquid reforming unit, and a plurality of adjustingunits (water purifying unit 161, ultrapure water-producing unit 162,degassing unit 173, filter 174, and the like) for adjusting the waterquality of the liquid LQ. The control unit CONT can specify at least oneof the plurality of adjusting units based on the result of measurementby the measuring unit 60 and report (inform) an information on thespecified adjusting unit, by the reporting unit INF. For example, whenthe dissolved gas concentration is judged as abnormal based on theresult of measurement by the DO meter or DN meter in the measuring unit60, the control unit CONT displays (reports), by using the reportingunit INF, an indication of which contents are to urge maintenance(inspection, replacement) of, for example, the degassing filter and/ordegassing pump of the degassing unit 173 among the plurality ofadjusting units. When the specific resistance of the liquid LQ is judgedas abnormal based on the result of measurement by the specificresistance meter in the measuring unit 60, the control unit CONTdisplays (reports), by using the reporting unit INF, an indication ofwhich contents are to urge maintenance (inspection, replacement) of, forexample, the ion exchange membrane of the water purifying device in themeasuring unit 60 among the plurality of adjusting units. Further, basedon the result of measurement by the specific resistance meter of themeasuring unit 60, when it is judged that the specific resistance valueof the liquid LQ is abnormal, the control unit CONT displays (reports),by using the reporting unit INF, an indication of which contents are tourge maintenance (inspection, replacement) of, for example, the ionexchange membrane of the water purifying system 16 among the pluralityof adjusting units. Furthermore, when the total organic carbon in theliquid LQ is judged as abnormal based on the result of measurement bythe TOC meter in the measuring unit 60, the control unit CONT displays(reports), by using the reporting unit INF, an indication of whichcontents are to urge maintenance (inspection, replacement) of, forexample, the UV lamp of the water purifying system 16 among theplurality of adjusting units. Moreover, when the amount of foreignsubstances (particles, bubbles) in the liquid LQ is judged as abnormalbased on the result of measurement of the particle counter in themeasuring unit 60, the control unit CONT displays (reports), by usingthe reporting unit INF, an indication of which contents are to urgemaintenance (inspection, replacement) of, for example, the filter 174 orthe particle filter of the water purifying system 16 among the pluralityof adjusting units. Further, when the amount of bacteria in the liquidLQ is judged as abnormal based on the result of analysis by the bacteriaanalyzer in the measuring unit 60, the control unit CONT displays(reports), by using the reporting unit INF, an indication of whichcontents are to urge maintenance (inspection, replacement) of, forexample, the UV lamp of the water purifying system 16 among theplurality of adjusting units. Furthermore, when the silica concentrationin the liquid LQ is judged as abnormal based on the result ofmeasurement by the silica meter in the measuring unit 60, the controlunit CONT displays (reports), by using the reporting unit INF, anindication of which contents are to urge maintenance (inspection,replacement) of, for example, the silica removing filter of the waterpurifying system 16 among the plurality of adjusting units.

Then, based on the information informed by the reporting unit INF, ameasure for setting the water quality of the liquid LQ to a desiredstate, including the above-described maintenance, and the like, is taken(Step S15). After this measure is taken, the control unit CONT executesagain the measuring operation for the water quality of the liquid LQ byusing the measuring unit 60. Then, the measure for setting the liquid LQto a desired state is taken until the result of measurement by themeasuring unit 60 is judged as not abnormal.

When the measuring operation using at least one of the optical measuringinstruments 300, 400, 500, and 600 at Step SA4 is completed, themeasuring operation using the measuring stage ST2 is ended or completed(Step SA5). Then, the control unit CONT instructs the start of theliquid immersion exposure process for the substrate P (Step SA6).

At this time, the substrate exchange operation at the substrate exchangeposition has been completed, and the substrate P before being exposed isheld on the substrate stage ST1. The control unit CONT brings, forexample, the measuring stage ST2 and the substrate stage ST1 intocontact with (or in proximity to) each other, and while maintainingtheir relative positional relationship, moves these stages ST1 and ST2in the XY plane to perform an alignment process with respect to thesubstrate P before the substrate P is exposed. At this point, aplurality of shot areas are provided on the substrate P, and alignmentmarks are provided corresponding to the shot areas respectively. Thecontrol unit CONT detects the alignment marks on the substrate P beforethe substrate P is exposed by the substrate alignment system, andcalculates the position coordinates with respect to the detectionreference positions of the substrate alignment system in the pluralityof short areas on the substrate P.

The control unit CONT simultaneously moves the substrate stage ST1 andthe measuring stage ST2 in the −Y direction by using the stage drivingunits SD1 and SD2 while maintaining the relative positional relationshipbetween the substrate stage ST1 and the measuring stage ST2 in the Yaxis direction. As explained with reference to FIG. 3, the control unitCONT moves the substrate stage ST1 and the measuring stage ST2 togetherin the −Y direction in an area including a position immediately below orunder the projection optical system PL in a state that the stages ST1and ST2 are in contact with (or in proximity to) each other. By movingthe substrate stage ST1 and the measuring stage ST2 together, thecontrol unit CONT moves the liquid, LQ retained in the space between thefirst optical element LS1 of the projection optical system LS1 and theupper surface 97 of the measuring stage ST2, from the upper surface 97of the measuring stage ST2 to the upper surface 95 of the substratestage ST1. The liquid immersion area LR of the liquid LQ filled in thespace between the first optical element LS1 of the projection opticalsystem PL and the measuring stage ST2 moves to the upper surface 97 ofthe measuring stage ST2, the upper surface 95 of the substrate stageST1, and the upper surface of the substrate P in this order accompanyingwith the movement of the measuring stage ST2 and the substrate stage ST1in the −Y direction. When the substrate stage ST1 and the measuringstage ST2 move together by a predetermined distance in the −Y direction,the liquid LQ is filled in a space between the first optical element LS1of the projection optical system PL and the substrate P. Namely, theliquid immersion area LR of the liquid LQ is arranged on the substrate Pin the substrate stage ST1. After moving the substrate stage ST1(substrate P) to the position below or under the projection opticalsystem PL, the control unit CONT withdraws the measuring stage ST2 to apredetermined position at which the measuring stage ST2 does not collidewith the substrate stage ST1.

Then, the control unit CONT performs liquid immersion exposure in thestep-and-scan manner for the substrate P supported on the substratestage ST1 in a state that the substrate stage ST1 and the measuringstage ST2 are separated from each other. When performing the liquidimmersion exposure for the substrate P, the control unit CONT forms theliquid immersion area LR of the liquid LQ on the substrate P by filling,the optical path space K1 for an exposure light beam LE between theprojection optical system PL and the substrate P, with the liquid LQ bythe liquid immersion mechanism 1, and the control unit CONT exposes thesubstrate P by irradiating the surface of the substrate P with theexposure light beam EL via the projection optical system PL and theliquid LQ (Step SA7). The liquid LQ filled in the optical path space K1between the projection optical system PL and the substrate P is a liquidLQ judged (confirmed) as being in a desired state without abnormality inwater quality at Step SA3. Therefore, the substrate P can besatisfactorily exposed through the liquid LQ in the desired state.

The control unit CONT executes the liquid immersion exposure operationin the step-and-scan manner for the substrate P to transfer the patternof the mask M to each of the plurality of shot areas on the substrate P.The movement of the substrate stage ST1 for exposure of the respectiveshot areas on the substrate P is performed based on the positioncoordinates of the plurality of shot areas on the substrate P and thebaseline information obtained as a result of the above-describedsubstrate alignment.

FIG. 7 is a drawing showing a state in which liquid immersion exposureis being performed for the substrate P. During the liquid immersionexposure, the liquid LQ in the liquid immersion area LR is in contactwith the substrate P, and information on the water quality of the liquidLQ recovered from the surface of the substrate P by the liquid recoverymechanism 20 is always measured (monitored) by the measuring unit 60.The result of measurement by the measuring unit 60 is outputted to thecontrol unit CONT. The control unit CONT stores the result ofmeasurement (monitor information) by the measuring unit 60 in the memoryMRY (Step SA8).

The control unit CONT stores the result of measurement of the liquid LQ,arranged on the substrate P, by the measuring unit 60 in the memory MRYby associating the result with the elapse of time. For example, thecontrol unit CONT stores the result of measurement by the measuring unit60 in the memory MRY by associating the result with the elapse of timeby defining the time when the liquid immersion area LR moves from thesurface of the measuring stage ST2 to the surface of the substrate stageST1 (surface of the substrate P) as a measurement start point(reference). In the following explanation, the result of measurement bythe measuring unit 60 concerning water quality of the liquid LQ, filledin the space between the projection optical system PL and the substrateP on the substrate stage ST1, which is stored by being associated withthe elapse of time, will be referred to as “third log information” asappropriate.

In this embodiment, a plurality of substrates P are successivelyexposed. When a plurality of substrates P are successively exposed, thecontrol unit CONT stores the results of measurements by the measuringunit 60 by associating the results with the substrates P. In thefollowing explanation, when a plurality of substrates P are successivelyexposed, information on the results of measurements by the measuringunit 60 concerning water quality of the liquid LQ, filled in the spacebetween the projection optical system PL and the substrate P on thesubstrate stage ST1, which is stored by being associated with thesubstrates P will be referred to as “fourth log information” asappropriate.

The control unit CONT stores the results of measurements by themeasuring unit 60 in the memory MRY by associating the results with shotareas to be exposed. The control unit CONT obtains positionalinformation of a shot area among the shot area in a coordinate systemdefined by the laser interferometer 94 for measuring the position of thesubstrate stage ST1 based on, for example, an output of the laserinterferometer 94; and the control unit CONT stores the result ofmeasurement measured by the measuring unit 60 when the exposure is beingperformed for the short area, of which positional information has beenobtained in the memory MRY, by associating the result with the shotarea. Between a point of time when the liquid LQ is measured by themeasuring unit 60 and a point of time when this measured liquid LQ isarranged on the substrate P (on the shot area), there is a time lagcorresponding to a distance between the recovery tube 22 and thesampling port (branched tube) of the measuring unit 60. Therefore, theinformation to be stored in the memory MRY may be corrected byconsidering the distance. In the following explanation, information onthe result of measurement by the measuring unit 60 stored by beingassociated with the shot area is referred to as “fifth log information”as appropriate.

The control unit CONT obtains information on the substrate P, asexplained below, based on the result of measurement of the liquid LQfilled in the space between the projection optical system PL and thepredetermined area 100 of the measuring stage ST2 measured by themeasuring unit 60 at Step SA2 and based on the result of measurement ofthe liquid LQ filled in the space between the projection optical systemPL and the substrate P measured by the measuring unit 60 at Step SA8(Step SA9).

FIG. 8 is a drawing showing an example of the substrate P. In FIG. 8,the substrate P has a base material 2 and a photosensitive material 3coated on a part of an upper surface 2A of the base material 2. The basematerial 2 includes, for example, a silicon wafer (semiconductor wafer).The photosensitive material 3 is coated by a predetermined thickness(for example, about 200 nm) on the area occupying most of the centralportion of the upper surface 2A of the base material 2. On the otherhand, the photosensitive material 3 is not coated on a peripheralportion 2As of the upper surface 2A of the base material 2, and the basematerial 2 is exposed at the peripheral portion 2As of the upper surface2A. Although side surfaces 2C and a lower surface (back face) 2B of thebase material 2 are not coated with the photosensitive material 3, theside surfaces 2C and/or the lower surface 2B, or the peripheral portion2As may be coated with the photosensitive material 3. In thisembodiment, a chemically amplified resist is used as the photosensitivematerial 3.

When the substrate P and the liquid LQ of the liquid immersion area LRcome into contact with each other, a part of the components of thesubstrate P is eluted into the liquid LQ. As described above, thephotosensitive material 3 of this embodiment is a chemically amplifiedresist, and this chemically amplified resist is formed by containing abase resin, a photo acid generator (PAG) contained in the base resin,and an amine-based substance called a quencher. When the liquid LQ comesinto contact with such a photosensitive material 3, a part of thecomponents of the photosensitive material 3, more specifically, PAGand/or amine-based substances are eluted into the liquid LQ. Also whenthe peripheral portion 2As of the base material 2 and the liquid LQ comeinto contact with each other, depending on the substances forming thebase material 2, there is a possibility that a part of the components(silicon) of the base material 2 is eluted into the liquid LQ. In thefollowing explanation, a substance or substances (PAG, amine-basedsubstances, silicon, and/or the like) eluted from the substrate P intothe liquid LQ will be referred to as “eluted substance” as appropriate.

The liquid LQ measured by the measuring unit 60 at Step SA8 is a liquidLQ filled in the space between the projection optical system PL and thesubstrate P, and is the liquid LQ after being brought into contact withthe substrate P. Therefore, the liquid LQ measured by the measuring unit60 contains eluted substances eluted from the substrate P into theliquid LQ. On the other hand, the liquid LQ measured by the measuringunit 60 at Step SA2 is a liquid LQ suppressed from being polluted,namely, a liquid LQ which contains no eluted substances. Therefore, bycomparing the result of measurement at Step SA2 and the result ofmeasurement at Step SA8, the control unit CONT can obtain information onthe eluted substances eluted from the substrate P into the liquid LQ asinformation on the substrate P. The above-described third, fourth, andfifth log information include the information on the eluted substanceseluted from the substrate P into the liquid LQ.

Information on the eluted substances eluted from the substrate P intothe liquid LQ includes various kinds of information such as the amountand properties (kinds) of the eluted substances. The control unit CONTcan obtain the amount of the eluted substances, eluted from thesubstrate P into the liquid LQ, based on the result of measurementconcerning water quality by the measuring unit 60 at Step SA2 and basedon the result of measurement concerning water quality by the measuringunit 60 at Step SA8.

For example, the control unit CONT can obtain, in particular, the amountof an eluted substance eluted from the photosensitive material 3 amongthe eluted substances eluted from the substrate P, based on the resultof measurement by the TOC meter 61 in the measuring unit 60.Alternatively, by providing a measuring instrument capable of measuringthe concentration of eluted substances in the liquid LQ, the amount ofthe eluted substances (concentration of the eluted substances in theliquid LQ) can be measured. Therefore, the control unit CONT can obtainthe amount of eluted substances eluted from the substrate P into theliquid LQ, based on the difference between the amount of the elutedsubstances measured at Step SA2 and the amount of the eluted substancesmeasured at Step SA8.

As the measuring unit 60, by providing a measuring instrument capable ofmeasuring the kinds of the eluted substances (photosensitive material 3,PAG, and the like) eluted from the substrate P, the kinds of the elutedsubstances can be identified.

Thus, the control unit CONT can obtain information on the substrate Psuch as the amount of eluted substances and the kind of thephotosensitive material 3 based on the result of measurement by themeasuring unit 60.

In this embodiment, the relationship between the substrate conditionsand the amount of eluted substances into the liquid LQ are obtained inadvance, and this relationship is stored in advance in the memory MRY.Here, the substrate conditions include conditions concerning thephotosensitive material 3 such as the kind (property) of thephotosensitive material 3 and conditions concerning the base materialsuch as the property (kind) of the base material 2, information whetheror not the peripheral portion 2As is formed (whether or not the basematerial 2 and the liquid LQ come into contact with other), and thelike. The substrate conditions also include coating conditions such asthe film thickness of the photosensitive material 3 when thephotosensitive material 3 is coated on the base material 2.

In this embodiment, a plurality of substrates P (lots) having mutuallydifferent substrate conditions are successively exposed, and informationon amounts of eluted substances corresponding to the plurality ofsubstrates P (lots) are stored in the memory MRY. Since the amount ofeluted substances into the liquid LQ changes according to the substrateconditions (properties and film thickness of the photosensitive material3, and the like), the relationship between the substrate conditions andthe amount of eluted substances into the liquid LQ can be obtained inadvance by, for example, an experiment and simulation.

Therefore, when the measured value (amount of eluted substances)measured by the measuring unit 60 when a substrate P with predeterminedsubstrate conditions is subjected to liquid immersion exposure isgreatly different from the amount of eluted substances according to thepredetermined substrate conditions stored in the memory MRY (when theresult of measurement by the measuring unit 60 is abnormal), the controlunit CONT judges that the substrate P is abnormal and can control theexposure operation.

When information on the substrate P held on the substrate stage ST1 isunknown, the information on the substrate P such as the kind and coatingconditions of the photosensitive material 3 on the substrate P to bemeasured can be estimated based on the result of measurement by themeasuring unit 60 (for example, the TOC meter 61) and the informationstored in the memory MRY (the relationship between the substrateconditions and the amount of eluted substances eluted into the liquidLQ).

As shown in FIG. 9, when the photosensitive material 3 is covered by athin film 4, the amount of eluted substances measured by the measuringunit 60 is small. Here, the thin film 4 covering the photosensitivematerial 3 is an antireflection film (top ARC), a topcoat film(protective film), or the like. In some cases, the thin film 4 is atopcoat film covering an antireflection film formed on thephotosensitive material 3. The topcoat film protects the photosensitivematerial 3 from the liquid LQ, and is made of, for example, afluorine-based liquid-repellent material. By providing the thin film 4,even when the substrate P and the liquid LQ come into contact with eachother, the elution of substance from the photosensitive material 3 intothe liquid LQ is suppressed. Therefore, when the photosensitive material3 is covered by the thin film 4, the difference between the result ofmeasurement (amount of eluted substances) at Step SA2 and the result ofmeasurement (amount of eluted substances) at Step SA8 becomes smallerthan in the case where the photosensitive material 3 is not covered bythe thin film 4. Therefore, the control unit CONT can also judge whetheror not the photosensitive material 3 is covered by the thin film 4 basedon the result of measurement by the measuring unit 60. Thus, the controlunit CONT is also capable of judging the presence or absence of the thinfilm 4 as information on the substrate P, based on the result ofmeasurement by the measuring unit 60.

Depending on the substance forming the thin film 4, there is apossibility that a predetermined substance of the photosensitivematerial 3 is eluted into the liquid via the thin film 4, or a substanceof the material forming the thin film 4 is eluted into the liquid.Therefore, information on the substrate P obtained based on the resultof measurement by the measuring unit 60 includes information on thematerial (substance) of the thin film 4 in addition to the presence orabsence of the thin film 4 on the photosensitive material 3.

In this embodiment, the substrate conditions and exposure conditions areset to be optimum so that the amount of eluted substances to be elutedfrom the substrate P into the liquid LQ (concentration of the elutedsubstances in the liquid LQ) becomes not more than a predeterminedpermissible value. The exposure conditions mentioned herein includeconditions of the liquid LQ, and include the property (kind) of theliquid LQ, the supply amount of the liquid LQ per unit time, thetemperature of the liquid LQ, the flow rate of the liquid LQ on thesubstrate P, and a liquid contact time during which the substrate P andthe liquid LQ are in contact with each other, and the like. When theamount of eluted substances eluted into the liquid LQ (concentration ofthe eluted substances in the liquid LQ) is not more than the permissiblevalue, the substrate P can be satisfactorily exposed.

In the following explanation, the permissible value concerning the waterquality of the liquid LQ filled in the space between the projectionoptical system PL and the substrate P will be referred to as “secondpermissible value” as appropriate. The second permissible value means apermissible value concerning water quality of the liquid LQ influencedby the object (herein the substrate P) arranged on the side of the imageplane of the projection optical system PL.

Information on the second permissible value concerning the eluted amountcan be obtained in advance through, for example, an experiment orsimulation. When the amount of eluted substances eluted from thesubstrate P into the liquid LQ is not less than the second permissiblevalue, there is a possibility that the concentration of the elutedsubstances in the liquid LQ becomes high and the transmittance of theliquid LQ lowers, thereby degrading the exposure accuracy through theliquid LQ such that the exposure light beam EL cannot satisfactorilyreach the surface of the substrate P through the liquid LQ. Further,when the amount of eluted substances eluted from the substrate P intothe liquid LQ is not less than the second permissible value, there is apossibility that a member (nozzle member 70, recovery tube 23, firstoptical element LS1, and the like) which comes into contact with theliquid LQ is polluted, the eluted substances adheres again to thesurface of the substrate P and act as foreign substances, and anadhesion mark (watermark) is formed. In this embodiment, by reducing theamount of eluted substances eluted from the substrate P into the liquidLQ to not more than the second permissible value, the above-describedproblem can be suppressed.

In this embodiment, substrates P (lots) having mutually differentsubstrate conditions are successively exposed, and in the memory MRY, aplurality of pieces of information on the second permissible value eachcorresponding to one of the substrates P (lots) is stored in advance. Inother words, information on the second permissible value is stored inadvance in the memory MRY for each of the substrates P (for each of thelots). For example, in a case that substrates P (lots) having a firstphotosensitive material and a second photosensitive material of whichproperties are different from each other, respectively, are successivelyexposed, even when the amount (concentration) of eluted substances fromthe first photosensitive material into the liquid LQ and the amount(concentration) of eluted substances from the second photosensitivematerial into the liquid LQ are the same, due to the properties(absorbance index, and the like) of the eluted substances, there is apossibility that a situation arises that the liquid containing theeluted substances from the second photosensitive material does not havea desired transmittance, whereas the liquid containing the elutedsubstances from the first photosensitive material has the desiredtransmittance. Therefore, in this embodiment, the second permissiblevalue is obtained in advance corresponding to each of the plurality ofsubstrates P (lots), and informations on the second permissible valueare stored in advance in the memory MRY. Thus, in this embodiment, thesecond permissible value of the amount of eluted substances is obtainedin advance individually for each of the substrate (for each of thelots), and is stored in the memory MRY.

To reduce the amount of eluted substances eluted from the substrate Pinto the liquid LQ (concentration of the eluted substances in the liquidLQ) to be not more than the second permissible value determined inadvance, a predetermined treatment may be performed in advance, beforeforming the liquid immersion area LR on the substrate P, for suppressingthe amount of eluted substances from the substrate P into the liquid LQin the liquid immersion area LR, such as performing the immersion of thesubstrate P in the liquid LQ which does not form the liquid immersionarea LR. Alternatively, by providing the thin film 4 as shown in FIG. 9,the elution of the substances from the photosensitive material 3 intothe liquid LQ can be suppressed. Accordingly, it is possible to suppressthe adhesion of foreign substance to the substrate P and the formationof adhesion mark, or the pollution of the member (nozzle member 70,recovery tube 23, and the like) which comes into contact with the liquidLQ.

The control unit CONT judges whether or not the result of measurement bythe measuring unit 60 is abnormal (Step SA10). Namely, the control unitCONT judges whether or not the measured value (amount of elutedsubstances) measured by the measuring unit 60 is not less than thesecond permissible value based on the second permissible valueconcerning the eluted substances determined in advance, and based on theresult of measurement by the measuring unit 60. Then, the control unitCONT controls the exposure operation based on the result of judgment.

When it is judged at Step SA10 that the result of measurement by themeasuring unit 60 is not abnormal, that is, when the result ofmeasurement (amount of eluted substances) by the measuring unit 60 isnot more than the second permissible value concerning the elutedsubstances determined in advance, the control unit CONT continues theliquid immersion exposure operation (Step SA11). At this time, thecontrol unit CONT can inform the result of measurement (monitorinformation) by the measuring unit 60 by the reporting unit INF.

After completing the liquid immersion exposure for the substrate P onthe substrate stage ST1 (Step SA12), the control unit CONT moves themeasuring stage ST2 by using the measuring stage driving unit ST2, andbrings the measuring stage ST2 into contact with (or proximity to) thesubstrate stage ST1. Then, the control unit CONT moves the liquidimmersion area LR of the liquid LQ from the upper surface 95 of thesubstrate stage ST1 to the upper surface 97 of the measuring stage ST2.After moving the liquid immersion area LR of the liquid LQ to thesurface of the measuring stage ST2, the control unit CONT moves thesubstrate stage ST1 to the substrate exchange position. At the substrateexchange position, the substrate P after being exposed is unloaded fromthe substrate stage ST1, and a substrate P before being exposed isloaded to the substrate stage ST1. Then, exposure process is performedfor this substrate P before being exposed.

Then, the control unit CONT successively exposes a plurality ofsubstrates P by repeating the above-described sequence. In the memoryMRY, the above-described first, second, third, fourth, and fifth loginformations are accumulated and stored. By using these loginformations, an exposure failure (error) can be analyzed (Step SA13).

On the other hand, when it is judged at Step SA10 that the result ofmeasurement by the measuring unit 60 is abnormal, that is, when theresult of measurement (amount of eluted substances) by the measuringunit 60 is not less than the second permissible value obtained inadvance concerning the eluted substances, the control unit CONT stopsthe exposure operation (Step SA16). At this time, for example, thecontrol unit CONT is capable of closing the flow channel in the supplytube 13 by driving the valve 13B provided in the supply tube 13 so as tostop the supply of the liquid LQ. After stopping the exposure operation,the liquid LQ remaining on the substrate P may be recovered by using thenozzle member 70 and the liquid recovery mechanism 20. Further, afterrecovering the liquid LQ remaining on the substrate P, the substrate Pmay be unloaded from the substrate stage ST1. By doing so, it ispossible to prevent problems such as formation of a large amount ofdefective shots (defective substrates) which would be otherwise causedif the exposure process were continued in the abnormal state.

The control unit CONT reports, by the reporting unit INF, the result ofmeasurement (monitor result) by the measuring unit 60 (Step SA17). Forexample, it is possible to indicate, by the reporting unit INF includinga display device, information on the amount of eluted substance causedby the photosensitive material 3 contained in the liquid LQ, informationon the amount of variation in the eluted substance with the elapse oftime, and information on the amount of eluted substances contained inthe liquid LQ (concentration of eluted substances in the liquid LQ)during exposure of a specific short area among the plurality of shotareas. When it is judged that the result of measurement by the measuringunit 60 is abnormal, the control unit CONT can report that the result ofmeasurement is abnormal by using the reporting unit INF in such a waythat an alarm (warning) is issued by the reporting unit INF. When anamount of eluted substances of not less than the second permissiblevalue is measured, the control unit can inform information to urgereview on the substrate conditions (for example, coating conditions ofthe photosensitive material 3) by using the reporting unit INF.Alternatively, concerning this substrate P, when an amount of elutedsubstances of not less than the second permissible value is measured,information to urge review on the exposure conditions (such as an amountof the liquid LQ to be supplied per unit time) can be informed by thereporting unit INF.

When a substance that should not be contained in the photosensitivematerial 3 used for the substrate P (lot) is measured, information onthis measurement can be reported by the reporting unit INF. Further,when a substance that should not be contained in the photosensitivematerial 3 used for the substrate P (lot) is measured, information tourge inspection of the photosensitive material 3 can be reported by thereporting unit INF. Furthermore, when an amount of eluted substances isnot less than the permissible value although the thin film 4 should havebeen coated, information to urge an inspection as to whether or not thethin film 4 is coated, and when it is coated, whether or not the coatingis satisfactory, can be reported by the reporting unit INF.

Alternatively, during the exposure of the substrate P, information onthe amounts of variation in TOC and dissolved gas concentration in theliquid LQ with the elapse of time, and information on the TOC anddissolved gas concentration in the liquid LQ during exposure of aspecific shot area among the plurality of shot areas can be indicated bythe reporting unit INF including a display device.

Even when it is judged at Step SA10 that abnormality has occurred in theliquid LQ, the control unit CONT can continue the exposure operation.Then, for example, during exposure of a specific shot area, when theresult of measurement by the TOC meter 61 of the measuring unit 60 isjudged as abnormal, the control unit CONT stores information that, theresult of measurement of TOC is abnormal, in the memory MRY as fifth loginformation by associating the result with this shot area. Then, afterexposing all of the shot areas, the control unit CONT can take ameasure, based on the fifth log information stored in the memory MRY,such that a shot area, of which pattern transfer accuracy may have beendegraded due to the abnormality in the result of measurement (the amountof eluted substances is not less than the permissible value), is removedor prevented from being exposed when the next overlaying exposure isperformed. When this shot area is inspected and no abnormality is foundin the formed pattern, this shot area is not removed and the deviceformation using this shot area is continued. Alternatively, the controlunit CONT may inform that the result of measurement by the TOC meter 61is abnormal by associating the result with the shot area. Thus, inaddition to indication of the result of measurement made by themeasuring unit 60 as monitor information in real time by the reportingunit INF, the control unit CONT can also indicate log information by thereporting unit INF.

In this embodiment, at Step SA3, when the measured value (water quality)of each of the items measured by the measuring unit 60 is not less thanthe first permissible value set in advance, the control unit CONT judgesthat the result of measurement by the measuring unit 60 is abnormal(abnormal water quality). The first permissible value of water qualitycan be properly determined according to the exposure process executedafter the measuring operation by the measuring unit 60. For example,after the measuring operation (Step SA2) by the measuring unit 60, themeasuring operation using the optical measuring instruments 300, 400,500, and 600 is performed (Step SA4), and according to targetmeasurement accuracies of the optical measuring instruments 300, 400,500, and 600, the first permissible value of water quality of the liquidLQ can be properly set. Specifically, in the case of exposing aplurality of lots (substrates P), when the optical measuring operationusing the optical measuring instruments 300, 400, 500, and 600 isperformed before exposing the lots (substrates P) and high measurementaccuracies are required for the first lot (first substrates), the firstpermissible value concerning water quality of the liquid LQ whenmeasuring the first lot (first substrates) through the liquid LQ is setto be strict. When comparatively rough measurement accuracies arepermitted for the second lot (second substrates) different from thefirst lot (first substrates), the first permissible value concerningwater quality of the liquid LQ when measuring the second lot (secondsubstrates) through the liquid LQ can be set to be comparatively lax.

Alternatively, the second permissible value concerning water quality ofthe liquid LQ can be properly set according to the target exposureaccuracy (target pattern transfer accuracy) for the substrate P.Specifically, in the case of exposing a plurality of lots (substratesP), when high exposure accuracy (pattern transfer accuracy) is requiredfor the first lot (first substrates), the second permissible valueconcerning water quality of the liquid LQ when exposing the first lot(first substrates) through the liquid LQ is set to be strict. On theother hand, when comparatively rough exposure accuracy (pattern transferaccuracy) is permitted for the second lot (second substrates) differentfrom the first lot (first substrates), the second permissible valueconcerning water quality of the liquid LQ when exposing the second lot(second substrates) through the liquid LQ can be set to be comparativelylax.

By doing so, desired exposure accuracies and measurement accuracies forthe respective first and second lots (first and second substrates) canbe obtained, and working ratio of the exposure apparatus EX can also beprevented from lowering. Namely, when the first and second permissiblevalues concerning water quality for the first lot and the first andsecond permissible values concerning water quality for the second lotare set to the same values, the water quality which is more thannecessary is required for the second lot. In this case, even whendesired water quality is obtained for the second lot, if the result ofmeasurement by the measuring unit 60 is not less than the firstpermissible value or the second permissible value, the measuringoperation or exposure operation is stopped as described above. Thus, theoperation of the exposure apparatus EX is stopped although desired waterquality has been obtained, thereby lowering the working ratio of theexposure apparatus EX. However, by properly setting the permissiblevalues concerning water quality of the liquid LQ according to the targetexposure accuracy and the like as described above, it is possible toprevent the problem such as lowering in working ratio of the exposureapparatus EX.

As described above, by providing the measuring unit 60 which measures atleast one of the property and the components of the liquid LQ filled ina space between the projection optical system PL and the predeterminedarea 100 of the measuring stage ST2, it is possible to accurately judge,based on the result of measurement, whether the liquid LQ filled in theoptical path space K1 is in a desired state or not (abnormal or not).Then, when the result of measurement by the measuring unit 60 isabnormal, by taking a proper measure for setting the liquid LQ to thedesired state, the exposure accuracy of the substrate P through theliquid LQ and the measurement accuracy of the optical measuringinstrument through the liquid LQ can be prevented from degrading.

In this embodiment, the result of measurement of the liquid LQ arrangedon the predetermined area 100 measured by the measuring unit 60 isstored as the first and second log informations in the memory MRY, andthe result of measurement of the liquid LQ arranged on the substrate Pmeasured by the measuring unit 60 is stored as the third, fourth, andfifth log informations in the memory MRY. For example, based on thefirst and second log information, maintenance (inspection, replacement)of each of the adjusting units (liquid reforming member and liquidreforming unit) constructing the liquid supply unit 11 can be performedin optimal timing. Also based on the first and second log information,the frequency of inspection and replacement can be set to be optimumaccording to each of the adjusting units. For example, from the firstlog information, when the measured value (amount of foreign substances)of the particle counter worsens with the elapse of time, an optimalreplacement time (replacement frequency) of the particle filter can beestimated and set based on the degree of change in the measured valuewith the elapse of time. Further, from the first and second loginformations, performance of the particle filter used can be set to beoptimal. For example, when the measured value of the particle counterrapidly worsens with the elapse of time, a high-performance particlefilter is used, and when the measured value of the particle counter doesnot greatly change, a comparatively low (inexpensive) particle filtercan be used so as to reduce the cost. By managing the exposure apparatusEX based on the first and second log informations in this manner, it ispossible to prevent a problem such that excessive (unnecessary)maintenance is performed and the working ratio is lowered, or that themaintenance is neglected and the liquid LQ in a desired state cannot besupplied.

Since the first log information is water quality information associatedwith elapse of time, the point of time at which the water quality startsdegrading can be specified. Therefore, the cause of exposure failure canbe analyzed by associating the cause with the elapse of time. Similarly,also by using the second log information, a failure (error) such as anexposure failure can be analyzed. When the substrate P is inspected inan inspection process as a post-process after the substrate P isexposed, by comparing and analyzing the result of inspection and thefirst and second log informations, the cause of the failure can beanalyzed and identified.

It is not necessarily indispensable that both of the first loginformation and the second log information are acquired. Instead, one ofthe first and second log informations may be acquired.

Since the third log information is water quality information associatedwith elapse of time, the amount of variation of the eluted substanceswith the elapse of time can be obtained based on the third loginformation. When the amount of variation greatly increases with theelapse of time, it can be judged that the photosensitive material 3 issoluble into the liquid LQ. When many exposure failures (patternfailures) occur in a specific lot or a specific shot area, the fourthlog information (or fifth log information) is referred to, and when themeasured value of the TOC meter when exposing this lot (or shot area) isabnormal, it can be analyzed that the cause of the pattern failures isthe eluted substances. For example, based on the fourth log information,a procedure or action, such as a selective inspection of the substrate Pexposed when the result of measurement by the measuring unit 60 isabnormal, can be taken after finishing the exposure. Further, based onthe fifth log information, when the liquid LQ is judged as abnormalduring exposure of a specific shot area, the control unit CONT can takea procedure or action to remove this specific shot area, not to exposethis shot area in the next overlaying exposure, or the like.Alternatively, the control unit CONT can also instruct an inspectionunit, which performs an inspection process, to perform an inspection ofthe specific shot area in greater detail than usual. By analyzing thecorrelation between pattern failures and eluted substances based on thethird, fourth, and fifth log informations in this manner, the cause ofthe failures (pattern failures) can be identified. Then, based on theresult of analysis, a procedure or action, such as review on thesubstrate conditions and/or exposure conditions, can be taken so as toprevent the pattern failures.

It is not necessarily indispensable that the third, fourth, and fifthlog informations are acquired. Instead, one or a plurality of the third,fourth, and fifth log informations can be omitted.

The control unit CONT can control the exposure operation and measuringoperation based on the result of measurement by the measuring unit 60.For example, as described above, before exposing the substrate P, aradiation amount (illuminance) of the exposure light beam EL is measuredwith the optical measuring instrument 600 (Step SA4), and based on theresult of measurement, the radiation amount (illuminance) of theexposure light beam EL is set (corrected) to be optimal, and then theexposure operation is started. However, for example, during exposure ofthe substrate P, due to TOC variation in the liquid LQ, the lighttransmittance of the liquid LQ may vary. When the light transmittance ofthe liquid LQ varies, the exposure amount (totalized exposure amount) onthe substrate P varies, and as a result, a problem may occur such asfluctuation in exposure line width of the device pattern formed in theshot areas. Therefore, the relationship between the TOC in the liquid LQand the transmittance of the liquid LQ is obtained and stored in thememory MRY in advance, and by controlling the exposure amount based onthe stored information and the result of measurement by the measuringunit 60 (TOC meter 61), the control unit CONT can prevent theabove-described problems. Namely, the control unit CONT derives atransmittance corresponding to the TOC variation in the liquid LQ basedon the stored information, and controls the exposure amount reaching thesubstrate P to be uniform. By controlling the exposure amount on thesubstrate P according to the change in TOC measured by the TOC meter 61,the exposure amount becomes uniform in a substrate (among shots) oramong substrates, thereby making it possible to suppress the fluctuationof exposure line width. The relationship between the TOC and lighttransmittance of the liquid LQ can be obtained by the measurementprocess using the optical measuring instrument 600 through the liquidLQ. In this embodiment, since a laser is used as a light source of theexposure light beam EL, the exposure amount on the substrate P can becontrolled by using a method in which energy (light amount) per 1 pulseis controlled, or the pulse number is controlled, or the like.Alternatively, the exposure amount on the substrate P can also becontrolled by controlling the scanning rate of the substrate P.

The control unit CONT can control the exposure operation and themeasuring operation based on the first log information. For example,when it is judged, based on the first log information, that the TOCvalue is worsening with elapse of time, the exposure apparatus EX makesthe exposure amount to be uniform among substrates P and reducesfluctuation in the exposure line width by controlling the exposureamount according to the elapse of time, based on the value (amount ofchange) according to the elapse of time of the TOC stored as the firstlog information.

As shown in FIG. 1, in the exposure apparatus EX, the liquid supplymechanism 10 includes a functional fluid supply unit 120. The controlunit CONT is capable of supplying a functional fluid LK from thefunctional fluid supply unit 120 of the liquid supply mechanism 10 toeach of the members which come into contact with the liquid LQ formingthe liquid immersion area LR, based on the first log information or theresult of measurement by the measuring unit 60, so as to clean themembers. For example, when the liquid LQ is not in a desired state andis polluted, namely, for example, the liquid LQ contains a large numberof bacteria, there is a possibility that the members which come intocontact with the liquid LQ, more, specifically, the lower surface 70A ofthe nozzle member 70, the internal flow channel of the nozzle member 70,the supply tube 13 connected to the nozzle member 70, the recovery tube23, the lower surface LSA of the first optical element LS1, the uppersurface 95 of the substrate stage ST1, and the upper surface 97 of themeasuring stage ST2 (including each of the upper surfaces of the opticalmeasuring instruments 300, 400, 500, and 600, and the predetermined area100), and the like is polluted. If each of the members is polluted, evenwhen a clean liquid LQ is supplied from the liquid supply unit 11, theliquid LQ is polluted due to contact with the members; and if the liquidimmersion area LR is formed by the polluted liquid LQ, the exposureaccuracy and measurement accuracy through the liquid LQ are degraded.

In addition, when the liquid immersion area LR of the liquid LQ isformed on the substrate P, the liquid LQ contains an eluted substancesuch as PAG eluted from the substrate P. Therefore, to the nozzle member70 which comes into contact with this liquid LQ containing the elutedsubstance, a pollutant derived from the eluted substance easily adheresto the nozzle member 70, and in particular, the pollutant easily adheresto a portion in the vicinity of the recovery ports 22 of the nozzlemember 70. When a mesoporous member or body is provided on the recoveryports 22, the pollutant also adheres to the mesoporous member or body.Then, if the nozzle member 70 and/or the mesoporous member or body areleft in the state that the pollutant is adhered thereto, even when aclean liquid LQ is supplied to the optical path space K1, the suppliedliquid LQ is polluted due to contact with the polluted nozzle member 70,and the like.

Therefore, the control unit CONT judges whether or not the members whichcome into contact with the liquid LQ are to be cleaned, based on theresult of measurement by the measuring unit 60. Namely, at Step SA3,when the control unit judges that the measured value is greater than thefirst permissible value (or second permissible value, or permissiblevalue for cleaning), based on the result of measurement by the measuringunit 60, then the control unit CONT cleans each of the members bysupplying a functional fluid LK having a cleaning effect (orsterilization effect) to each of to the members from the functionalfluid supply unit (cleaning unit) 120 which constructs a part of theliquid supply mechanism 10.

When supplying the functional fluid LK from the functional fluid supplyunit 120, the control unit CONT makes the lower surface LSA of theprojection optical system PL to face or to be opposite to the uppersurface 97 of the measuring stage ST2 or the upper surface 95 of thesubstrate stage ST1. Alternatively, a dummy substrate DP as describedlater may be held on the substrate stage ST1 to face or to be oppositeto the lower surface LSA of the projection optical system PL.

When cleaning the respective members, the control unit CONT opens theflow channel in the supply tube 19 by driving the second valve 19Bprovided in the supply tube 19 which connects the functional fluidsupply unit 120 and the liquid supply unit 11, and closes the flowchannel in the return tube 18 by the first valve 18B. Accordingly, thefunctional fluid LK is supplied from the functional fluid supply unit120 to the liquid supply unit 11. The functional fluid LK supplied fromthe functional fluid supply unit 120 flows through the liquid supplyunit 11 and then flows through the supply tube 13 and the internal flowchannel (supply flow channel) of the nozzle member 70, and is suppliedto the side of the image plane of the projection optical system PLthrough the supply ports 12. When the functional fluid supply unit 120supplies the functional fluid LK, similarly to when the liquid immersionexposure operation is performed, the liquid recovery mechanism 20performs a liquid recovery operation. Therefore, the functional fluid LKfilled on the side of the image plane of the projection optical systemPL is recovered through the recovery ports 22 and flows through therecovery tube 23, and is then recovered by the liquid recovery unit 21.The functional fluid LK flows through the flow channels (supply tube 13,recovery tube 23, nozzle member 70, and the like) of the liquidimmersion mechanism 1 to clean these flow channels.

Since the functional fluid LK filled on the side of the image plane ofthe projection optical system PL also comes into contact with the lowersurface (liquid contact surface) LSA of the first optical element LS1and the lower surface (liquid contact surface) 70A of the nozzle member70, the functional fluid LK cleans the lower surfaces LSA and 70A.Further, in a state that the immersion area of the functional fluid LKis formed, it is possible to clean a wide area in the upper surface 97of the measuring stage ST2 or in the upper surface 95 of the substratestage PT1 by two-dimensionally moving the measuring stage ST2 (orsubstrate stage ST1) in the XY direction with respect to the immersionarea of the functional fluid LK. Thus, by performing the operation forforming the immersion area of the functional fluid LK by the sameprocedures as in the case of the liquid immersion exposure operation,each of the members can be simultaneously and efficiently cleaned.

As cleaning procedure by using the functional fluid LK, after thefunctional fluid LK is supplied from the functional fluid supply unit120, the operations for supplying and recovering the functional fluid LKare t continued for a predetermined period of time, by the sameprocedures as in the case of the liquid immersion exposure operation, soas to form the liquid immersion area of the functional fluid LK on theside of the image plane of the projection optical system PL. It is alsoallowable that the functional fluid LK is heated and then fed into theflow channels in the liquid supply mechanism 10 and the liquid recoverymechanism 20. After a predetermined period of time has been elapsed, theoperations for supplying and recovering the functional fluid LK arestopped. In this state, the functional fluid LK is retained on the sideof the image plane of the projection optical system PL, and is in animmersion state. After maintaining the immersion state for apredetermined period of time, the control unit CONT performs theoperations for supplying and recovering pure water for a predeterminedperiod of time by the liquid supply mechanism 10 and the liquid recoverymechanism 20 to form a liquid immersion area of pure water on the sideof the image plane of the projection optical system PL. Accordingly, thepure water flows through the flow channels of the liquid supplymechanism 10 and the liquid recovery mechanism 20, and the flow channelsare cleaned by the pure water. In addition, by the immersion area of thepure water, the lower surface LSA of the first optical element LS1 andthe lower surface 70A of the nozzle member 70 are also cleaned.

After completing the cleaning process, the control unit CONT fills theliquid LQ in the space between the projection optical system PL and thepredetermined area 100 of the measuring stage ST2 by using the liquidimmersion mechanism 1, and is capable of confirming whether or not thecleaning process was satisfactorily performed, namely, whether or notthe liquid LQ is in a desired state, by measuring the liquid LQ by usingthe measuring unit 60.

It is preferable that the functional fluid LK is composed of a materialhaving no influence on each of the members. In this embodiment, hydrogenperoxide is used as the functional fluid LK. Among the members, a membermade of a material having no resistance against the functional fluid LKmay be removed before the cleaning process using the functional fluidLK.

In this embodiment, it is described that the cleaning process isperformed by controlling the operations of the liquid supply mechanism10 including the functional fluid supply unit 120 based on the result ofmeasurement by the measuring unit 60. However, as a matter of course, itis also allowable that the cleaning process is performed atpredetermined time intervals (for example, monthly or yearly) withoutreferring to the result of measurement by the measuring unit 60. As asource of pollution of the members (the nozzle member 70, the firstoptical element LS1, and the like) which come into contact with theliquid LQ are not only polluted liquid LQ and an eluted substance fromthe substrate P. There is a possibility that the members are alsopolluted, for example, by an impurity floating in the air and adheringto the members. In such a case also, by performing the cleaning processat predetermined time intervals without referring to the result ofmeasurement by the measuring unit 60, the pollution of the members andthe pollution of the liquid LQ which comes into contact with the memberscan be prevented.

In the first embodiment described above, the water quality measurementwhen the liquid immersion area is formed on the substrate P may beomitted. Namely, in the flowchart of FIG. 6, Steps SA9 to SA11, SA16,and SA17 may be omitted.

Second Embodiment

Next, a second embodiment will be described. In the followingexplanation, constitutive parts or components which are same as orequivalent to as those in the embodiment described above are designatedby the same reference numerals, and any explanation therefor will besimplified or omitted.

In the above-described first embodiment, the liquid LQ is filled in thespace between the projection optical system PL and the predeterminedarea 100 of the measuring stage ST2, and in this state, the waterquality of the liquid LQ is measured (Step SA2), and based on the resultof measurement, when it is judged that the water quality of the liquidLQ has no abnormality (Step SA3), a measuring operation using at leastone of the optical measuring instruments 300, 400, 500, and 600 isperformed. In this embodiment, as shown in FIG. 10, in a state that theliquid LQ is filled in a space between the projection optical system PLand the optical measuring instrument (here, for example, the sensor 400)on the measuring stage ST2, the control unit CONT performs a measuringoperation by using the sensor 400, and concurrently performs themeasuring operation using the sensor 400 and at least a part of thewater quality measuring operation using the measuring unit 60. Namely,the control unit CONT supplies and recovers the liquid LQ by the liquidimmersion mechanism 1 in a state that the control unit CONT makes theprojection optical system PL and the upper surface 401 of the sensor 400provided on the measuring stage ST2 to face each other (to be oppositeto each other). Accordingly, the liquid LQ is filled in the optical pathspace K1 between the projection optical system PL, the sensor 400 andthe sensor 400 can perform a measurement process through the liquid LQ,and the measuring unit 60 can perform a measurement process for waterquality of the liquid LQ recovered by the liquid recovery mechanism 20.As described above, the upper surface 401 of the sensor 400 is coatedwith, for example, “Cytop (trademark)” so as not to pollute the liquidLQ. Therefore, the measuring unit 60 can measure the liquid LQ which issuppressed from being polluted. Here, the explanation is given for anexample in which the measuring operation using the sensor 400 and themeasuring operation using the measuring unit 60 are concurrentlyperformed. However, as a matter of course, it is also allowable that themeasuring operations using the reference member 300 and the sensors 500,600 and the measuring operation using the measuring unit 60 can beconcurrently performed.

In this manner, by concurrently performing the measuring operation usingthe optical measuring instrument through the liquid LQ and the waterquality measuring operation using the measuring unit 60, the measurementtime using the measuring stage ST2 can be shortened and the throughputcan be improved.

Third Embodiment

Next, a third embodiment will be explained. In the above-describedembodiment, when the water quality of the liquid LQ is measured with themeasuring unit 60, the control unit CONT supplies and recovers theliquid LQ by the liquid immersion mechanism 1 in a state that theprojection optical system PL and the measuring stage ST2 are made toface (to be opposite to) each other, however, as shown in FIG. 11, it isalso allowable that the control unit CONT supplies and recovers theliquid LQ by the liquid immersion mechanism 1 in a state that theprojection optical system PL and a dummy substrate DP held on thesubstrate stage ST1 are made to face each other, and measures the liquidLQ in contact with the dummy substrate DP by using the measuring unit60. The dummy substrate DP is a different member from the substrate Pfor device producing, and has substantially same size and shape as thoseof the substrate P. On the upper surface of the dummy substrate DP, atleast an area which comes into contact with the liquid LQ is formed soas not to pollute the liquid LQ. In this embodiment, for the uppersurface of the dummy substrate DP, PFA treatment is performed similarlyto the first embodiment. Alternatively, the dummy substrate DP may bemade of PFA. Also in this case, the measuring unit 60 can accuratelymeasure the water quality of the liquid LQ without being influenced bythe object (the dummy substrate DP in this case) arranged on the side ofthe image plane of the projection optical system PL.

Alternatively, the following construction may also be adopted in which apartial (or whole) area of the upper surface 95 of the substrate stageST1 is formed so as not to pollute the liquid LQ by performing, forexample, the PFA treatment therefor; and when measuring the waterquality of the liquid LQ by using the measuring unit 60, in a state thatthe projection optical system PL and the upper surface 95 of thesubstrate stage ST1 are made to face each other (to be opposite to eachother), the liquid LQ is supplied and recovered by the liquid immersionmechanism 1 and the water quality measurement is performed by themeasuring unit 60.

Still alternatively, it is also allowable that, in a state that thesubstrate stage ST1 and a predetermined member other than the measuringstage ST2 are made to face (to be opposite to) the projection opticalsystem PL, the liquid LQ is supplied and recovered by the liquidimmersion mechanism 1, and water quality measurement using the measuringunit 60 is performed. In this case, the predetermined member has apredetermined area formed so as not to pollute the liquid LQ. Thispredetermined member may be provided movably, by a driving unitincluding an actuator, on the side of the image plane of the projectionoptical system PL.

Alternatively, the measuring unit 60 may be provided in the measuringstage ST2. In this case, the measuring unit 60 includes measuringinstruments (TOC meter, particle counter, and the like) embedded in themeasuring stage ST2, and a sampling port (hole) formed in the uppersurface 97 of the measuring stage ST2. When the liquid LQ is measured bythe measuring instrument, the liquid immersion area LR of the liquid LQis formed on the side of the image plane of the projection opticalsystem PL, the liquid immersion area LR and the measuring stage ST2 arerelatively moved, the liquid immersion area LR is arranged on thesampling port, and the liquid LQ is made to flow into the sampling port.The measuring instrument measures the liquid LQ acquired via thesampling port. Here, PFA treatment or the like is performed for theupper surface 97 of the measuring stage ST2 so as not to pollute theliquid LQ. Also in this construction, the measuring unit 60 canaccurately measure the water quality of the liquid LQ. Similarly, themeasuring unit 60 may be provided in the substrate stage ST1.

Fourth Embodiment

Next, a fourth embodiment will be explained with reference to FIG. 12.The feature of this embodiment is that a measuring unit 60 (60A, 60B)measures water quality of the liquid LQ at a plurality (herein, two) ofmeasuring positions in the flow channels of the liquid immersionmechanism 1.

In FIG. 12, the liquid immersion mechanism 1 includes a supply tube 13for supplying the liquid LQ and a recovery tube 23 for recovering theliquid LQ. The measuring unit 60 includes a first measuring unit 60A formeasuring the water quality of the liquid LQ at a predetermined position(first position) C1 in the supply tube 13 and a second measuring unit60B for measuring the water quality of the liquid LQ at a predeterminedposition (second position) C2 in the recovery tube 23. The first andsecond measuring units 60A and 60B have a construction substantiallyequivalent to that of the measuring unit 60 of the first embodimentexplained with reference to FIG. 5. The measuring unit 60 measures thewater quality of the liquid LQ at the first position C1 and the secondposition C2 in the flow channels, constructing the liquid immersionmechanism 1, by using the first and second measuring units 60A and 60B,respectively. The measurement results of the first and second measuringunits 60A, 60B are outputted to the control unit CONT.

The control unit CONT can obtain the state of the flow channel betweenthe first position C1 and the second position C2 in flow channels of theliquid immersion mechanism 1, based on the result of measurement by thefirst measuring unit 60A, namely the result of measurement of waterquality of the liquid LQ at the first position C1, and on the result ofmeasurement by the second measuring unit 60B, namely the result ofmeasurement of water quality of the liquid LQ at the second position C2.In this embodiment, between the first position C1 and the secondposition C2 constructing the flow channels of the liquid immersionmechanism 1, the nozzle member 70 is provided. Therefore, the controlunit CONT can obtain the state of the nozzle member 70 based on theresults of measurements by the first and second measuring units 60A and60B. Specifically, the control unit CONT can obtain the state ofpollution of the flow channel between the first position C1 and thesecond position C2 including the nozzle member 70 based on the resultsof measurements by the first and second measuring units 60A and 60B.

When obtaining the pollution state of the flow channel between the firstposition C1 and the second position C2 by using the first and secondmeasuring units 60A and 60B, the control unit CONT supplies and recoversthe liquid LQ by the liquid immersion mechanism 1 in a state that thecontrol unit CONT makes the lower surface LSA (lower surface 70A of thenozzle member 70) of the projection optical system PL face (to beopposite to) the predetermined area 100 of the upper surface 97 of themeasuring stage ST2, and the control unit CONT fills the liquid LQ inthe space between the projection optical system PL and the predeterminedarea 100. Accordingly, the measuring unit 60 (second measuring unit 60B)can measure the water quality of the liquid LQ without being influencedby the object arranged on the side of the image plane of the projectionoptical system PL, and can accurately measure the state of the flowchannel between the first position C1 and the second position C2.

When the flow channel between the first position C1 and the secondposition C2 is polluted, the result of measurement by the firstmeasuring unit 60A and the result of measurement by the second measuringunit 60B become different from each other. Accordingly, the control unitCONT can obtain the state of the pollution of the flow channel betweenthe first position C1 and the second position C2 including the nozzlemember 70, based on the results of measurements by the first and secondmeasuring units 60A and 60B. When the flow channel between the firstposition C1 and the second position C2 is polluted, for example, when anorganic matter is present inside the recovery tube 23 and/or inside therecovery flow channel (internal flow channel) of the nozzle member 70, ameasured value measured by the TOC meter of the second measuring unit60B becomes greater than a measured value measured by the TOC meter ofthe first measuring unit 60A. Therefore, the control unit CONT canobtain the state of pollution of the flow channel between the firstposition C1 and the second position C2 based on the results ofmeasurements by the first and second measuring units 60A and 60B.

Between the first position C1 and the second position C2, the nozzlemember 70 having the supply ports 12 for supplying the liquid LQ to theoptical path space K1 and the recovery ports 22 for recovering theliquid LQ from the optical path space K1 is arranged, and when the flowchannel between the first position C1 and the second position C2 ispolluted, the liquid LQ is consequently polluted when the liquid LQpasses through this flow channel, and the polluted liquid LQ fills theoptical path space K1.

Therefore, the control unit CONT judges whether or not maintenance for,in particular, the flow channel between the first position C1 and thesecond position C2 in the flow channels constructing the liquidimmersion mechanism 1 is to be performed, according to the result ofmeasurement by the measuring unit 60. Specifically, the control unitCONT judges whether or not the results of measurements (the differencebetween the measured value measured by the first measuring unit 60A andthe measured value measured by the second measuring unit 60B) by themeasuring unit 60 are abnormal, and based on the result of judgment,judges whether or not the maintenance is to be performed.

Here, the phrase that “the result of measurement of the measuring unit60 is abnormal” includes a situation that a difference between themeasured value measured by the first measuring unit 60A and the measuredvalue measured by the second measuring unit 60B is not less than apredetermined permissible value; the state (water quality) of the liquidLQ is not in the desired state by passing through the flow channelbetween the first position C1 and the second position C2; and theexposure process and measurement process through the liquid LQ cannot beperformed in a desired state when the liquid LQ fills the optical pathspace K1. Information on this permissible value can be obtained inadvance through, for example, an experiment or simulation.

As described above, since the nozzle member 70 comes into contact withthe liquid LQ containing eluted substance or substances eluted from thesubstrate P, the nozzle member 70 is easily polluted. If the pollutionof the nozzle member 70 is left as it is, even when a clean liquid LQ issupplied into the optical path space K1, the supplied liquid LQ comesinto contact with the polluted nozzle member 70 and the like, and thenis polluted. In this embodiment, by providing the nozzle member 70between the first position C1 and the second position C2, the controlunit CONT can accurately obtain the state of pollution of the nozzlemember 70 based on the results of measurements by the first and secondmeasuring units 60A and 60B. Then, when the nozzle member 70 ispolluted, by taking a proper procedure or action for cleaning the nozzlemember 70, the liquid LQ filled in the optical path space K1 can bemaintained at a desired state.

The control unit CONT can judge whether or not maintenance is to beperformed, according to the results of measurements by the measuringunit 60 (first and second measuring units 60A and 60B), namely,according to the result of judgment as to whether or not the results ofmeasurements by the measuring unit 60 (difference between the measuredvalue measured by the first measuring unit 60A and the measured valuemeasured by the second measuring unit 60B) are abnormal. When it judgesthat maintenance is to be performed for the flow channel between thefirst position C1 and the second position C2, the predeterminedmaintenance is performed. As the maintenance, similarly to the firstembodiment, the functional fluid LK having a cleaning function issupplied from the functional fluid supply unit 120 into the flowchannels of the liquid immersion mechanism 1, including the portionbetween the first position C1 and the second position C2, to clean theflow channels. Alternatively, as the maintenance, the nozzle member 70is detached or separated from the supply tube 13 and the recovery tube23, namely, the nozzle member 70 is removed from the exposure apparatusEX, and is cleaned by a predetermined cleaning unit separate from theexposure apparatus EX. Alternatively, the maintenance may be exemplifiedby replacement of the nozzle member 70 with a new one (clean one),cleaning by an operator, and the like.

After the maintenance, the control unit CONT supplies and recovers theliquid LQ by the liquid immersion mechanism 1, and can confirm whetheror not the flow channel including the nozzle member 70 has become clean,by measuring the water quality of the liquid LQ at the first and secondpositions C1 and C2.

In this embodiment, the state of the flow channel between the firstposition C1 and the second position C2 including the nozzle member 70 ismeasured, however, as a matter of course, it is also possible to obtainthe state of the flow channel between arbitrary measuring positions, inthe flow channels of the liquid immersion mechanism 1, which do notinclude the nozzle members 70. For example, in the supply tube 13, bysetting a portion in the vicinity of the position at which the supplytube 13 is connected to the liquid supply unit 11 as the first positionC1, and setting a position in the vicinity of the position at which thesupply tube 13 is connected to the nozzle member 70 as the secondposition C2, the state of the supply tube 13 can be obtained. Based onthe results of measurements by the measuring units, a procedure oraction can be taken, for example, whereby the functional fluid LK is fedinto the supply tube 13; the supply tube 13 is removed from the exposureapparatus EX and cleaned; the supply tube 13 is replaced with a new(clean) one; or the like.

In this embodiment, the measuring unit 60 measures the water quality ofthe liquid LQ at each of the two points, namely in the first and secondpositions C1 and C2 in the flow channels of the liquid immersionmechanism 1. However, as a matter of course, the water quality of theliquid LQ can be measured at three or more arbitrary positions in theflow channels of the liquid immersion mechanism 1. In this case, themeasuring units are set or placed at a plurality of predeterminedpositions in the flow channels of the liquid immersion mechanism 1, andthe control unit CONT can obtain the state of flow channels between therespective measuring positions, based on the results of measurements ofwater quality of the liquid LQ at the plurality of measuring positions.

Thus, the control unit CONT measures water quality of the liquid LQ at aplurality of measuring positions along the flow direction of the liquidLQ, in the flow channels of the liquid immersion mechanism 1, by usingthe measuring unit 60, and the control unit CONT obtains the state ofthe flow channels between the measuring positions based on the resultsof measurements of water quality at the respective measuring positions.Accordingly, in the flow channels constructing the liquid immersionmechanism 1, it is possible to identify a certain position at which thewater quality of the liquid LQ is changed, thereby easily identifyingthe cause of the change. The control unit CONT can also identify acertain portion in which abnormality occurs, based on the results ofmeasurements by the measuring units. Then, by reporting (informing) thatan abnormality occurs in the certain portion by using the reporting unitINF, it is possible to urge investigation of this portion so as toquickly realize quick restoration from the failure.

Other Embodiments

The measuring unit 60 in each of the first to fourth embodiments isprovided on the exposure apparatus EX in a fixed manner. However, forexample, it is also allowable that the measuring unit 60 is connected tothe exposure apparatus EX (supply tube 13 or recovery tube 23) at thetime of maintenance of the exposure apparatus or in a predeterminedtiming so as to periodically or irregularly perform water qualitymeasurement of the liquid LQ.

In each of the first to fourth embodiments, the measuring unit 60includes a plurality of measuring instruments (61, 62, 63, and 64) andis connected to the recovery tube 23 (or the supply tube 13) via aplurality of branched tubes, respectively. However, it is also allowablethat one branched tube (port) is provided for the recovery tube 23 (orthe supply tube 13), and the plurality of measuring instruments (61, 62,63, and 64) are successively connected to the two ports while exchangingthe measuring instruments to be connected to the two ports to performwater quality measurement of the liquid LQ. Alternatively, in the secondembodiment, the first measuring unit 60A is connected to the supply tube13 via a branched tube, and the second measuring unit 60B is connectedto the recovery tube 23 via a branched tube. However, it is alsoallowable to mutually connect one measuring unit, the first position C1of the supply tube 13 and the second position C2 of the recovery tube23, and by switching the flow channels by using valves or the like,after measuring water quality of the liquid LQ at the first position C1(second position C2), the water quality of the liquid LQ at the secondposition C2 (first position C1) is measured.

In the first to fourth embodiments, when it is desired to measure thecomponents of the bacteria in the liquid LQ, it is allowable that theliquid LQ to be supplied is sampled at a predetermined timing andmeasured (analyzed) by using a measuring device (analyzer) providedseparately from the exposure apparatus EX. Also, when measuringparticles, bubbles, dissolved oxygen and the like, it is allowable that,instead of the in-line system, the liquid LQ is sampled at apredetermined timing and measured by a measuring device providedseparately from the exposure apparatus EX. Alternatively, for example,it is also allowable that the branched tubes 61K to 64K are providedwith valves, and by operating the valves, the liquid LQ flowing in thesupply tube 13 is made to flow into the measuring unit 60 at apredetermined timing and is intermittently measured. On the other hand,by always supplying the liquid LQ flowing in the supply tube 13 to themeasuring unit 60 and by continuously measuring the liquid LQ, themeasurement by the measuring unit 60 can be made stable.

In the first to fourth embodiments, the branched tubes 61K, 62K, 63K,and 64K are connected to the recovery tube 23 between the liquidrecovery unit 21 and the nozzle member 70, and the measuring unit 60measures the liquid LQ branched from the recovery tube 23. In this case,it is desired that the branched tubes are arranged at positions as nearto the nozzle member 70 (near to the recovery ports 22) as possible.

In the first to fourth embodiments, the branched tubes 61K, 62K, 63K,and 64K function as sampling ports for sampling the liquid LQ flowing inthe recovery tube 23, and the measuring unit 60 measures the liquid LQsampled by the branched flow channels branched at intermediate positionsin the recovery tube 23, between the nozzle member 70 and the liquidrecovery unit 21. However, it is also allowable that the sampling portsare attached at positions in vicinity of, for example, the recoveryports 22 of the nozzle member 70, and that the measuring unit 60measures the liquid LQ flowing at positions in vicinity of the recoveryports 22.

As described above, the liquid LQ used in the embodiments is pure water.Pure water is easily acquired in large quantities in a semiconductorproducing factory, or the like, and has an advantage that the pure waterhas no harmful influence on a photoresist on the substrate P, an opticalelement (lens), and the like. Pure water also has no harmful influenceon the environment, and has a very low content of impurities, so thatthe pure water is expected to have a function to wash the surface of thesubstrate P and the surface of the optical element provided at the endsurface of the projection optical system PL. When the purity of purewater supplied from a factory or the like is low, the exposure apparatusmay have an ultrapure water-producing unit.

It is approved that the refractive index n of pure water (water) withrespect to the exposure light beam EL having a wavelength of about 193nm is approximately 1.44. When the ArF excimer laser beam (wavelength:193 nm) is used as the light source of the exposure light beam EL, thenthe wavelength is shortened on the substrate P by 1/n, i.e., to about134 nm, and a high resolution is obtained. Further, the depth of focusis magnified about n times, i.e., about 1.44 times as compared with thevalue obtained in the air. Therefore, when it is enough to secure anapproximately equivalent depth of focus as compared with the case of theuse in the air, it is possible to further increase the numericalaperture of the projection optical system PL. Also in this viewpoint,the resolution is improved.

In this embodiment, the optical element LS1 is provided at the end ofthe projection optical system PL, and by this lens, the opticalproperty, for example, aberrations (spherical aberration, comaaberration, and the like) of the projection optical system PL can beadjusted. The optical element which is attached to the end of theprojection optical system PL may be an optical plate used for adjustingthe optical property of the projection optical system PL. Alternatively,the optical element may be a plane-parallel through which the exposurelight beam EL is transmissive.

When the pressure, which is generated by the flow of the liquid LQ, islarge between the substrate P and the optical element disposed at theend portion of the projection optical system PL, it is also allowablethat the optical element is tightly fixed so that the optical element isnot moved by the pressure, instead of allowing the optical element to beexchangeable.

In the embodiment of the present invention, the space between theprojection optical system PL and the surface of the substrate P isfilled with the liquid LQ. However, for example, it is also allowablethat the space is filled with the liquid LQ in such a state that a coverglass formed of a plane-parallel is attached to the surface of thesubstrate P.

In the case of the projection optical system PL concerning each of theembodiments, the optical path space, which is on the side of the imageplane of the optical element arranged at the end portion, is filled withthe liquid. However, it is also possible to adopt such a projectionoptical system in which the optical path space, on the side of the maskin relation to the optical element LS1, is also filled with the liquid,as disclosed in International Publication No. 2004/019128.

The liquid LQ is water in the embodiment of the present invention.However, the liquid LQ may be any liquid other than water. For example,when the light source of the exposure light beam EL is the F₂ laser, theF₂ laser beam is not transmissive through water. Therefore, the liquidLQ may be, for example, a fluorine-based fluid such as fluorine-basedoil and perfluoropolyether (PFPE) through which the F₂ laser beam istransmissive. In this case, the portion, which makes contact with theliquid LQ, is subjected to a liquid-attracting treatment by forming, forexample, a thin film with a substance, including fluorine, which has amolecular structure with small polarity, on the portion. Alternatively,other than the above, it is also possible to use, as the liquid LQ,those (for example, cedar oil) which have the transmittance with respectto the exposure light beam EL, which have the refractive index as highas possible, and which are stable against the photoresist coated on thesurface of the substrate P and the projection optical system PL. Also inthis case, the surface treatment is performed depending on the polarityof the liquid LQ to be used.

The substrate P, which is usable in the respective embodiments describedabove, is not limited to the semiconductor wafer for producing thesemiconductor device. Those applicable include, for example, a glasssubstrate for the display device, a ceramic wafer for the thin filmmagnetic head, and a master plate (synthetic silica glass, siliconwafer) for the mask or the reticle to be used for the exposureapparatus.

As for the exposure apparatus EX, the present invention is alsoapplicable to the scanning type exposure apparatus (scanning stepper)based on the step-and-scan system for performing the scanning exposurewith the pattern of the mask M by synchronously moving the mask M andthe substrate P as well as the projection exposure apparatus (stepper)based on the step-and-repeat system for performing the full fieldexposure with the pattern of the mask M in a state in which the mask Mand the substrate P are allowed to stand still, while successivelystep-moving the substrate P.

As for the exposure apparatus EX, the present invention is alsoapplicable to the exposure apparatus based on the system in which thefull field exposure is performed on the substrate P by using aprojection optical system (for example, the dioptric type projectionoptical system having a reduction magnification of ⅛ and including nocataptric element) with a reduction image of a first pattern in a statein which the first pattern and the substrate P are allowed tosubstantially stand still. In this case, the present invention is alsoapplicable to the full field exposure apparatus based on the stitchsystem in which the full field exposure is further performed thereafteron the substrate P by partially overlaying a reduction image of a secondpattern with respect to the first pattern by using the projectionoptical system in a state in which the second pattern and the substrateP are allowed to substantially stand still. As for the exposureapparatus based on the stitch system, the present invention is alsoapplicable to the exposure apparatus based on the step-and-stitch systemin which at least two patterns are partially overlaid and transferred onthe substrate P, and the substrate P is successively moved. In theembodiment described above, the light-transmissive type mask (reticle)is used, in which the predetermined light-shielding pattern (or phasepattern or dimming or light-reducing pattern) is formed on thelight-transmissive substrate. However, in place of such a reticle, asdisclosed, for example, in U.S. Pat. No. 6,778,257, it is also allowableto use an electronic mask on which a transmissive pattern, a reflectivepattern, or a light-emitting pattern is formed on the basis of theelectronic data of the pattern to be subjected to the exposure. Thepresent invention is also applicable to the exposure apparatus(lithography system) in which a line-and-space pattern is formed on awafer W by forming interference fringes on the wafer W as disclosed inthe pamphlet of International Publication No. 2001/035168.

The invention is also applicable to an exposure apparatus in which themeasuring stage ST2 is omitted and only the substrate stage ST1 forholding the substrate P is provided. In this case, the predeterminedarea 100 formed so as not to pollute the liquid LQ may be provided onthe substrate stage ST1, or the above-described dummy substrate DP maybe held on the substrate stage ST1 to be used as the predetermined area.In each of the embodiments described above, although the exposureapparatus including the projection optical system PL is described as anexample, the invention is also applicable to an exposure apparatus andan exposure method which do not use the projection optical system PL.Even when the projection optical system PL is not used, a substrate isirradiated with the exposure light beam via an optical member such as alens, and a liquid immersion area is formed in a predetermined spacebetween this optical member and the substrate.

The present invention is also applicable to a twin-stage type exposureapparatus. In the twin-stage type exposure apparatus, the predeterminedarea formed so as not to contaminate the liquid LQ may be formed on theupper surface of at least one of two stages holding substrates. Thestructure and the exposure operation of the twin-stage type exposureapparatus are disclosed, for example, in Japanese Patent ApplicationLaid-open Nos. 10-163099 and 10-214783 (corresponding to U.S. Pat. Nos.6,341,007, 6,400,441, 6,549,269, and 6,590,634), Published JapaneseTranslation of PCT International Publication for Patent Application No.2000-505958 (corresponding to U.S. Pat. No. 5,969,441), and U.S. Pat.No. 6,208,407, contents of which are incorporated herein by referencewithin a range of permission of the domestic laws and ordinances of thestate designated or selected in this international application.

The above-described embodiments adopt an exposure apparatus in which theliquid is locally filled between the projection optical system PL andthe substrate P. However, the invention is also applicable to a liquidimmersion exposure apparatus which performs exposure in a state that anentire surface of a substrate to be exposed is immersed in a liquid asdisclosed, for example, in Japanese Patent Application Laid-open No.6-124873, Japanese Patent Application Laid-open No. 10-303114, and U.S.Pat. No. 5,825,043. The structure and the exposure operation of such anexposure apparatus are described in detail in U.S. Pat. No. 5,825,043,contents of which are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the state designatedor selected in this international application.

As for the type of the exposure apparatus EX, the present invention isnot limited to the exposure apparatus for the semiconductor deviceproduction for exposing a semiconductor device pattern on the substrateP. The present invention is also widely applicable, for example, to theexposure apparatus for producing the liquid crystal display device orfor producing the display as well as the exposure apparatus forproducing, for example, the thin film magnetic head, the image pickupdevice (CCD), the reticle, or the mask.

When the linear motor is used for the substrate stage ST1 and/or themask stage MST, it is allowable to use any one of those of the airfloating type based on the use of the air bearing and those of themagnetic floating type based on the use of the Lorentz's force or thereactance force. Each of the stages ST1, ST2 and MST may be either ofthe type in which the movement is effected along the guide or of theguideless type in which no guide is provided. An example of the use ofthe linear motor for the stage is disclosed in U.S. Pat. Nos. 5,623,853and 5,528,118, contents of which are incorporated herein by referencerespectively within a range of permission of the domestic laws andordinances of the state designated or selected in this internationalapplication.

As for the driving mechanism for each of the stages ST1, ST2 and MST, itis also allowable to use a plane motor in which a magnet unit providedwith two-dimensionally arranged magnets and an armature unit providedwith two-dimensionally arranged coils are opposed to one another, andeach of the stages ST1, ST2 and MST is driven by the electromagneticforce. In this case, any one of the magnet unit and the armature unitmay be connected to the stage ST1, ST2 and MST, and the other of themagnet unit and the armature unit may be provided on the side of themovable surface of the stage ST1, ST2 and MST.

The reaction force, which is generated in accordance with the movementof the stages ST1 and ST2, may be mechanically released to the floor(ground) by using a frame member so that the reaction force is nottransmitted to the projection optical system PL, as described inJapanese Patent Application Laid-open No. 8-166475 (U.S. Pat. No.5,528,118). The contents of U.S. Pat. No. 5,528,118 are incorporatedherein by reference within a range of permission of the domestic lawsand ordinances of the state designated or selected in this internationalapplication.

The reaction force, which is generated in accordance with the movementof the mask stage MST, may be mechanically released to the floor(ground) by using a frame member so that the reaction force is nottransmitted to the projection optical system PL as disclosed in JapanesePatent Application Laid-open No. 8-330224 (U.S. Pat. No. 5,874,820). Thecontents of U.S. Pat. No. 5,874,820 are incorporated herein by referencewithin a range of permission of the domestic laws and ordinances of thestate designated or selected in this international application.

As described above, the exposure apparatus EX according to theembodiment of the present invention is produced by assembling thevarious subsystems including the respective constitutive elements asdefined in claims so that the predetermined mechanical accuracy, theelectric accuracy, and the optical accuracy are maintained. In order tosecure the various accuracies, those performed before and after theassembling include the adjustment for achieving the optical accuracy forthe various optical systems, the adjustment for achieving the mechanicalaccuracy for the various mechanical systems, and the adjustment forachieving the electric accuracy for the various electric systems. Thesteps of assembling the various subsystems into the exposure apparatusinclude, for example, the mechanical connection, the wiring connectionof the electric circuits, and the piping connection of the air pressurecircuits in correlation with the various subsystems. It goes withoutsaying that the steps of assembling the respective individual subsystemsare performed before performing the steps of assembling the varioussubsystems into the exposure apparatus. When the steps of assembling thevarious subsystems into the exposure apparatus are completed, theoverall adjustment is performed to secure the various accuracies as theentire exposure apparatus. It is desirable that the exposure apparatusis produced in a clean room in which, for example, the temperature andthe cleanness are managed.

As shown in FIG. 13, a microdevice such as a semiconductor device isproduced by performing, for example, a step 201 of designing thefunction and the performance of the microdevice, a step 202 ofmanufacturing a mask (reticle) based on the designing step, a step 203of producing a substrate as a base material for the device, asubstrate-processing (exposure process) step 204 of exposing a patternof the mask on the substrate by using the exposure apparatus EX of theembodiment described above, a step 205 of assembling the device(including a dicing step, a bonding step, and a packaging step), and aninspection step 206, and the like. The substrate-processing step 204includes the processing described in relation to the drawings such asFIG. 6 and the like.

1. An exposure apparatus which exposes a substrate by irradiating thesubstrate with an exposure light beam via an optical member, comprising:an object which is arranged on a light-exit side of the optical memberand is different from the substrate; a liquid immersion mechanism whichfills an optical path space between the optical member and the objectwith a liquid; and a measuring unit which measures at least one ofproperty and components of the liquid in a state that a liquid immersionarea is formed on the object.
 2. The exposure apparatus according toclaim 1, wherein the optical member is at least a part of the projectionoptical system.
 3. The exposure apparatus according to claim 2, wherein:the object has a predetermined area formed so as not to pollute theliquid; and the liquid immersion mechanism fills the liquid in a spacebetween the projection optical system and the predetermined area on theobject.
 4. The exposure apparatus according to claim 2, wherein: theliquid immersion mechanism has a liquid recovery mechanism whichrecovers the liquid; and the measuring unit measures the liquidrecovered by the liquid recovery mechanism.
 5. The exposure apparatusaccording to claim 4, wherein: the liquid recovery mechanism has arecovery flow channel in which the recovered liquid flows and a branchedflow channel branched from the recovery flow channel at an intermediateposition in the recovery flow channel; and the measuring unit measuresthe liquid flowing in the branched flow channel.
 6. The exposureapparatus according to claim 2, wherein the object is movable on a sideof an image plane of the projection optical system.
 7. The exposureapparatus according to claim 6, wherein the object includes a firstmovable member which is movable while holding the substrate.
 8. Theexposure apparatus according to claim 6, further comprising a firstmovable member on which the substrate is held, wherein the objectincludes a dummy substrate different from the substrate, the dummysubstrate being held on the first movable member.
 9. The exposureapparatus according to claim 6, wherein the object includes a secondmovable member which is movable while carrying an optical measuringinstrument which optically performs measurement concerning an exposureprocess.
 10. The exposure apparatus according to claim 9, wherein: ameasuring operation using the optical measuring instrument is performedin a state that the liquid is filled in a space between the projectionoptical system and the optical measuring instrument on the secondmovable member; and the measuring operation by the optical measuringinstrument and at least a part of a measuring operation by the measuringunit are concurrently performed.
 11. The exposure apparatus according toclaim 2, comprising a control unit which controls an exposure operationbased on a result of measurement by the measuring unit.
 12. The exposureapparatus according to claim 11, wherein the control unit judges whetheror not the result of measurement by the measuring unit is abnormal, andcontrols the exposure operation based on a result of judgment.
 13. Theexposure apparatus according to claim 11, wherein the control unit setsa permissible value concerning at least one of the property and thecomponents of the liquid, and controls the exposure operation based onthe permissible value and the result of measurement by the measuringunit.
 14. The exposure apparatus according to claim 13, wherein thepermissible value is determined according to an exposure process to beexecuted after a measuring operation by the measuring unit.
 15. Theexposure apparatus according to claim 11, comprising a reporting unitwhich reports the result of measurement by the measuring unit, whereinthe control unit issues a warning by using the reporting unit when theresult of measurement is abnormal.
 16. The exposure apparatus accordingto claim 11, wherein: the liquid immersion mechanism has a flow channelin which the liquid flows; and the liquid immersion mechanism includes aplurality of adjusting devices which are provided at predeterminedpositions, respectively, in the flow channel of the liquid immersionmechanism and are capable of adjusting at least one of the property andthe components of the liquid; and the control unit specifies at leastone of the plurality of adjusting devices based on the result ofmeasurement by the measuring unit.
 17. The exposure apparatus accordingto claim 11, wherein the control unit obtains information on thesubstrate based on a first result of measurement of the liquid, filledin a space between the projection optical system and the object,measured by the measuring unit and on a second result of measurement ofthe liquid, filled in a space between the projection optical system andthe substrate, measured by the measuring unit.
 18. The exposureapparatus according to claim 17, wherein the information on thesubstrate includes information on an eluted substance eluted from thesubstrate into the liquid.
 19. The exposure apparatus according to claim18, wherein the control unit controls the exposure operation based on apermissible value determined in advance concerning the eluted substanceand on the result of measurement by the measuring unit.
 20. The exposureapparatus according to claim 17, wherein: the substrate has a basematerial and a photosensitive material coated on the base material; andthe information on the substrate includes information on thephotosensitive material.
 21. The exposure apparatus according to claim1, wherein: the liquid immersion mechanism includes a supply flowchannel for supplying the liquid and a recovery flow channel forrecovering the liquid; the measuring unit measures the liquid at a firstposition in the supply flow channel of the liquid immersion mechanismand the liquid at a second position in the recovery flow channel of theliquid immersion mechanism; and the control unit obtains a state of aflow channel between the first position and the second position based ona result of measurement of the liquid at the first position and a resultof measurement of the liquid at the second position.
 22. The exposureapparatus according to claim 21, wherein: the liquid immersion mechanismhas a nozzle member which has at least one of a supply port whichsupplies the liquid and a recovery port which recovers the liquid; andthe nozzle member is provided between the first position and the secondposition.
 23. The exposure apparatus according to claim 22, wherein thecontrol unit judges a condition of the nozzle member based on the resultof measurement of the measuring unit.
 24. The exposure apparatusaccording to claim 22, wherein the control unit judges whether cleaningof the nozzle member is necessary or not, based on the result ofmeasurement of the measuring unit.
 25. The exposure apparatus accordingto claim 22, wherein the control unit judges whether the nozzle memberis polluted or not, based on the result of measurement of the measuringunit.
 26. The exposure apparatus according to claim 21, wherein thecontrol unit judges whether or not maintenance of the flow channelbetween the first position and the second position is to be performed,according to the result of measurement by the measuring unit.
 27. Theexposure apparatus according to claim 1, comprising a memory whichstores the result of measurement by the measuring unit.
 28. The exposureapparatus according to claim 27, wherein the memory stores the result ofmeasurement by the measuring unit by associating the result with elapseof time.
 29. The exposure apparatus according to claim 27, wherein aplurality of substrates are successively exposed; and the memory storesthe result of measurement by the measuring unit by associating theresult with each of the substrates.
 30. The exposure apparatus accordingto claim 1, wherein: an optical path space for the exposure light beambetween the projection optical system and the substrate is filled withthe liquid by the liquid immersion mechanism; and the substrate isexposed by irradiating a surface of the substrate with the exposurelight beam via the projection optical system and the liquid.
 31. Adevice producing method using the exposure apparatus as defined inclaim
 1. 32. An exposure method for exposing a substrate through aliquid, comprising: a first step of forming a liquid immersion area onan object different from the substrate; a second step of inspecting astate of the liquid in a state that a liquid immersion area is formed onthe object; a third step of adjusting an exposure condition based on aresult of inspection; and a fourth step of exposing the substrate underthe adjusted exposure condition by irradiating the substrate with anexposure light beam through the liquid in a liquid immersion area formedon the substrate.
 33. The exposure method according to claim 32, whereina liquid supply system used for forming the liquid immersion area at thefirst step is same as a liquid supply system used for forming the liquidimmersion area at the fourth step.
 34. The exposure method according toclaim 32, wherein the object is arranged at the first step on a positionat which the substrate is placed for exposure.
 35. The exposure methodaccording to claim 32, wherein a surface of the object which comes intocontact with the liquid is formed of a material which generates nosubstance in the liquid.
 36. The exposure method according to claim 32,wherein a state of the liquid recovered from the liquid immersion areais inspected at the second step.
 37. The exposure method according toclaim 32, further comprising inspecting a state of the liquid in theliquid immersion area formed on the substrate at the fourth step,wherein a result of the inspection and the result of inspection at thesecond step are compared with each other.
 38. The exposure methodaccording to claim 32, wherein the state of the liquid is one selectedfrom a group consisting of a physical property of the liquid, aninclusion in the liquid, and a dissolved gas in the liquid.
 39. Theexposure method according to claim 32, further comprising asubstrate-exchange step of exchanging the substrate, wherein the firstand second steps are performed in the substrate-exchange step.
 40. Adevice producing method comprising: exposing a substrate by the exposuremethod as defined in claim 32; and processing the developed substrate.